Analytics is used by google to improve adwords product (most of google revenue). Nothing is free.
Here is the most common reason why GA is free:
Here is 2 another ones?
- Provide advertiser tools to speed their site (real-user monitoring)
- Increase ads relevance (hidden)
Since 2011, google ranking consider site speed. Faster are sites, more search people will be done.
How can GA be used by google to increase ads relevance?
In order to understand this concept, let's look at google eco-system.
If a user visit several site monitored by google Analytics, GA information can be leverage to better recommend ads anywhere and improve google search ads.
With GA, you get quite interesting information about users: their behavior, the content and sites they visit, their frequency and time spent and this across multiple sites. GA is an amazing source of user information.
In order to get better customized ads, you need:
- session data (behavior, site visited, content type, frequency, etc.)
- aggregate data to user data
- get more information about the user (no simply an id, a google+ or gmail account)
- Google analytics (same sessions id between sites)
- gmail login (get a uniq id)
- Chrome browser (control browser, control browser global id)
- google+ and gmail account (user info)
The next biggest challenge is leveraging the social graph, which explain google+ war against facebook.
The ad platform has to leverage GA, gmail, google+ etc. to improve its search.