Agreed.. people starting using Google before AdSense existed.

Hexstream · on Feb 18, 2008

I'd say that still gives them more visibility.

I know I wouldn't be aware of their omnipresence as much if they didn't write "Ads by Google" alongside their ads. Insofar as ads is about building brand recognition and I recognize Google better, then "Ads by Google" is an ad within the ad from my perspective (by the way I'm 100% for it).