Unique visitors – Google Analytics metrics

rapporto visitatori su google analytics

The number or unique visitors is one of the first metrics that we read, when we enter the Google Analytics panel for our website. It can be found under Audience –> Overview.

From the unique visitors metric we can understand several informations, for example:

  • how many individuals (approximatively) accessed my website, during a given period?
  • With respect to the promotional activities I’m carrying out, my audience is increasing or not?
  • Overall, how many individuals I reached from the beginning of my activity?
We can say that the larger the unique visitors value is, the greater my website’s or brand’s popularity is and / or the more effective my promotional activities are.
So this number basically tells me how good I was in increasing my website’s audience, in quantitative terms.

At a first glance, the meaning of unique visitors seems easy to understand, but this metric gets often confused with other metrics, as “visits”, and two other metrics that were used by Google Analytics and now have been eliminated: visitors and absolute unique visitors.

Nowadays, visitors and unique visitors mean the same thing: how many individual browsers accessed the website, in a given period (a browser is the piece of software you are using surf the internet and view this page in this moment: Internet Explorer, Firefox, Chrome, Safari, etc.).

For example, if a person (let’s call it: John) this morning visited my website from his PC at home, and this evening came back using his iPad, he actually used two different browsers to access the website, and Google Analytics will count two unique visitors even if the person is the same (unless his browsers were synchronized and other technicalities, but ok, you got the meaning…).

More exactly, when a user visits your website for the first time, Google Analytics “tags” his browser with a visitor identifier that gets stored in a 2-years-lasting GA’s __utma cookie. Google Analytics counts the unique visitors as the sum of the __utma cookies that accessed the website in the selected period.

Therefore, if a user this morning visits my website, in the afternoon deletes the cookies in his browser (e.g. for privacy concerns) and in the evening visits again my website with the same browser, it will still be counted as two unique visitors.

To summarize, due to several technical reason related to the way this metric is measured, it is reasonable to assume that the unique visitors value that you read in Google Analytics is slightly overestimating the number of real individuals that accessed your website.

It should be noted that it is not possibile to sum values of unique visitors from different periods. For example, if on January my website had 100 unique visitors, and on February it had 200 unique visitors, I can’t conclude that on January and February it had 100+200 = 300 unique visitors, because an unknown part of the visitors in January may have visited the website also in February.

Hope it was helpful!

Made to stick by Chip Heath and Dan Heath

Made To Stick by Chip Heath and Dan Heath is one of my favorites books.  It is about why some ideas becomes popular and stick into people’s minds, and why others don’t.

The authors, after a thorough research among a large amount of stories, proverbs, legends, etc., concluded that an idea, in order to be memorable, should have the following characteristics:

  1. Simplicity: the idea should be as simple as possibile and its most important concepts should be communicated first.
  2. Unexpectedness: the idea should surpise the listener, forcing him to stop and think.
  3. Concreteness: the idea should be connected to real-world analogies.
  4. Credibility: the idea should be communicated by, or referred to, a credible person (e.g. an authority in the field) or include data and evidences, enforcing its credibilty
  5. Emotional: ideas that create emotions are most easily remembered by people.
  6. Story: when an idea is communicated as a story, people get more interested and connected.

By the way, the achronym forms the word “S.U.C.C.E.S.”… 🙂

I find this book very easy to read and interesting, as it makes use of the same “sticking” tips in its own writing and you can immediately verify how they work on you!

Definitely one of the best book I read in communication, Made To Stick is a must-read for all people in charge of marketing a product.

Highly recommended.

Vote: 5/5



Other great books by Chip Heath and Dan Heath:

Defining KPIs for Your Website

Metaphor of KPIs usefulness: fuel level indicator

Once you have defined your goals for your online business and scheduled all the activities that need to be carried out for reaching these goals, you have to identify some parameters for monitoring the performance of your activities, in order to understand if you are walking on the right path to the goal.

These parameters are known as Key Performance Indicators, or KPIs.

KPIs for an online business are like a compass for a ship: if we don’t have them, we’ll sail in sight!

Moreover, defining KPIs is necessary to make our data analysis structured and effective: how many times we open Google Analytics, we look at the visits (+5%, good!), the keywords (great! they have found me searching “usain bolt shoes”!) , etc. and then we close it, without understanding if we are getting closer to our goal or having taken any useful decision?

The output of the KPIs definition is a list of parameters to be periodically monitored. Some KPIs will allow us to evaluate the overall performance of a group of aspects of our online business, while some others will be focused on a more specific area.

Every time we open Google Analytics, we’ll check the values of the KPIs and try to understand if everything is on track or if there are areas who need corrective actions to be taken in order to navigate our business toward its goals.

Let’s go back to the example of our previous post. The goal 1 of our running shoes online store was to realize 30.000 sales the first year.

So, The KPI 1 could be defined as:

KPI 1 = Number_of_sales / month

This KPI, perhaps the most significant one for measuring the performance of our online business, is strictly related to goal 1: the larger the KPI 1, the closer we are getting to goal 1.

Suppose that, thanks to our promotional activities, word of mouth and traffic from search engines, our website is visited every month by a certain number of visitors potentially interested in buying running shoes.

Of course, we want this number to be as large as possibile: the more potentially interested visitors come to our site, the higher is the probability to sell our shoes.

Therefore, a second KPI could be defined as:

KPI 2: number_of_visitors / month

This KPI is correlated to the amount of visibility our website has and could be influenced both by the popularity of our brand and/or by the promotional activities we are carrying out.

In general, we can assume that the number of sales per month are (more or less) proportional to this KPI.

One other interesting question is: on average, how many people do I need to bring to my website to generate one sale?

This data could be monitored via a third KPI, that could be defined as:

KPI 3: number_of_sales / number_of_visitors

The KPI 3 reflects our overall efficiency to convert visitors into customers. This depends on several factors, including the efficiency of our promotional activities and the efficiency of our website.

In other words, the KPI 3 gets larger if all the following events take place often:

  • our promotional activities bring to our website people potentially interested in buying running shoes
  • these people like the shoes we sell on our website
  • these people trust our brand, the website and the payment methods; accept the purchase and shipping terms; etc.
  • these people take the decision to buy the shoes and complete the buying process on the website

Each of these bullets is related to a specific aspect of our business and influences its overall efficiency in converting visitors into customers: this efficiency is indicated by KPI 3.

Let’s have a look at the three KPIs we defined so far. KPI 1 allows us evaluating the overall business performance with respect to our goal 1, while KPI 2 and KPI 3 provide us with indications on two more specific aspects: the visibility of our website and the efficiency of our business in converting visitors into customers.

Note that:

KPI 1 = Number_of_sales / month =

= (Number_of_visitors / month) * (Number_of_sales / Number_of_visitors) =

= KPI 2 * KPI 3

KPI 1 equals the multiplication between KPI2 and KPI3: this means that if we want to sell a lot of shoes per month, we need to bring traffic to the website and make our online business an efficient “converting machine”, that turns into customers as many visitors as possible. If one of the two KPIs is small, we will have difficult times to reach our sales goal.

However, if we want to understand deeper which aspect of our business is successfully working and which not, we need to define some indicators even more specific about our activities.

For example, number_of_sales / number_of_visitors_from_Facebook, will be and indicator about the efficiency of our promotional activities on Facebook with respect to the sales. It give us clues for answering questions like the followings:

  • The number of sales generated by visitors from Facebook is adequate to the money I’m spending to carry out these promotional activities?
  • These Facebook promotional activities are more or less efficient than those I’m carrying out on other social networks, e.g. on Twitter?
  • Should I move my budget from promoting on Facebook to some other more efficient activities?

The output of our KPI definition is a list of parameters along with a description of what they indicate:

KPI Definition What it indicates
1 Number_of_sales / month Overall performance with respect to goal 1
2 Number_of_visitors / month Visibility level of the website (brand popularity, promotional activities, SEO, etc.)
3 Number_of_sales / Number_of_visitors Overall efficiency in converting visitors into customers

To summarize, for all those people whose work is understanding the health status of an online business and taking corrective actions to drive the business toward its goals, it’s crucial to define, from the beginning, all the KPIs that need be monitored for evaluating the performance of the business’s key activities.

From the next post, we will start to talk about the most popular tool for collecting and analyzing many website data: Google Analytics.


  • Have you defined and written down all relevant KPIs for your online business?
  • Near every KPI, have you written down which aspect of your online business it reflects?

Defining Goals for Your Website

Runner finishing the boston marathon

Defining goals for your website is the key starting point of your activities that may strongly influence the success probability of your online business.

In facts, it’s only after this process of goals definition that we can:

  • design and develop a website that works
  • create a logical and structured working plan
  • understand if we are going in the right direction or not

Goals are useful if they are: not too many, clear, quantitative, measurable and with a deadline assigned.

Setting quantitative goals it’s not easy, especially if we are just starting-up and we don’t have a past experience concerning the results we may achieve.

However, it’s very important to attempt estimating which business results could be obtained by our activity within a certain time span, even if our estimate it’s not fully accurate at the beginning: we’ll be able to refine it when we’ll have more data available.

Suppose that our website is an online store specialized in selling running shoes.

Based on our online market research (in future posts we will see how to do it), we define our goals as follows:

  1. 30.000 sales in 1 year
  2. 1.000 contacts of potential customers in 1 year

Great! These goals are a few, clear, quantitative, measurable and have a deadline assigned! 🙂

Now, our next step is to define a strategy that will allow us to reach these goals. Defining a strategy translates in listing several activities that need to be carried out. For any online business, these activities will likely include:

  • website optimization (SEO, landing page optimization, etc.)
  • online advertising (e.g. Google AdWords)
  • social network marketing (on Facebook, Twitter, etc.)
  • email marketing
  • off-line promotional activities (flyers, radio & tv commercials, etc.)

Moreover, when the business is running, we’ll have to constantly check the performance of our activities and take the necessary corrective actions in order to make the online business capable of reaching our goals within the deadline.

Therefore, once our strategy is in place and all activities are listed and scheduled, it is crucial to identify some measurable parameters that will reflect the status of our online business performance: the Key Performance Indicators, or KPIs. We will talk about KPIs in the next post.


  • have you estimated reasonable business results that can achieve with your online activity, within a certain time span?
  • based on this estimate, have you defined some clear, quantitative, measurable goals and have you assigned a deadline?

My Blog Starts Today

Metaphor of my blog starting today: image of a new born baby

Today my personal blog is born. Here I will post my ideas, thoughts, articles, tips & tricks about Web Analytics and SEO applied to online business (but not only).

Google Analytics, SEO, online business development are both my daily job and my deep passion, and I would really like to share all I know, and learn, on these topics.

I’m not a native english speaker, but I hope this blog will be clear and understandable by everyone.

I’m lucky to work as Analytics and SEO specialist for a digital marketing consulting agency, 3rdPLACE s.r.l., and I truly love this job.

However, the path that led me to my current work was not that straight… I took a degree in Aerospace Engineering in 2004, and then worked for the aerospace department of University of Rome for 7 years, developing software for interplanetary spacecrafts navigation (the great and famous Delta-DOR correlator, now in use at the European Space Agency) and participating in the preparation of the radio-science experiment of the BepiColombo mission to the planet Mercury.

During those years, my deep love with internet and online business grew up. In 2007 I started my own business, that is still running: Incidi! – The Best Independent Music Shop, a store (but not only) that allows independent musicians to sell their music online.

It was a great experience under every point of view and thanks to it I have learned many of the things I know today about online business and web development.

However, in 2011 I felt the need to work for a digital marketing consulting agency, where I could learn from my colleagues and work for clients of different kinds. After a short transitional period, I had the luck to find my current job at 3rdPLACE s.r.l..

Aside from my job, I love reading books on my kindle, especially those self-help books focused on business, start-ups and personal skills development: that’s one of my favorite hobbies!

So, I hope you will enjoy reading my blog! Don’t hesitate to write me for any suggestions and to leave your comments.

Cheers! 🙂