The Merciful Google!!!

Do you remember the history of Gmail? At first, you must had an invitation to subscribe to it. I was searching a lot those days and at last one of my friends (that had a Gmail account) invited me to the Gmail. About 1 year ago, Gmail opened its subscription for the public and skipped its beta stage.

Google always claimed that its income source was the "Text Ads". But some days ago, I found a new setting in my Gmail account: Web Clips.
You can freely turn off the "Web Clips" to disable showing ads!!! Now the question is: What is the Google's revenue for hosting Gmail?! Is Google love us and doesn't like to bother us by even "Text Ads"?! I hope the Google's revenue wasn't and isn't our "Personal Information".