AdSense opened to publishers via self-service, expanding the content network for AdWords advertisers

Google added a self-service option to AdSense, letting approved website publishers place contextually targeted AdWords text ads on their pages and earn from clicks. For advertisers this broadened the content network beyond the large publishers Google had signed up when content targeting began in March 2003.

At launch the program was limited to English-language sites, and publishers gained access to a pool of more than 100,000 AdWords advertisers. The Screaming Frog timeline dates this to May 2003; the press release is dated June 18, 2003.