[codeptualize]

I forgot the most important reason! Data for ads.

Delivering ads is based on data about you, so you get the most effective ads. Your browsing data is really valuable data in that sense.

If you read about the privacy controls in chrome you get a pretty good idea of what they collect:

> Your topics of interest are noted by Chrome and are based on your recent browsing history. Sites can also store info with Chrome about your interests. As you keep browsing, Chrome may be asked to share stored info about ad topics or site-suggested ads to help give you a more personalized ad experience. To measure the performance of ads, limited types of data can be shared among sites and apps.

https://support.google.com/chrome/answer/13355898

It's all about ads.