When it comes to Google lagging in social networking, former chief executive Eric Schmidt said the buck stops with him.

"Four years ago, I wrote memos and I did nothing about those," Schmidt, Google's executive chairman, said in response to a question from AllThingsD's Kara Swisher at the annual D9 conference in Rancho Palos Verdes, Calif., tonight. "CEOs should take responsibility. I screwed up."

File photo of Google&39's Eric Schmidt.

The admission comes as Google tries to match Facebook's popular "Like" feature for Web sites, where users click on an icon to show their admiration for a Web site. Tomorrow, Google is expected to announce +1 for Web sites, something of a copycat feature that gives users who are logged into their Google accounts the ability to show some favor for sites with its technology.

Schmidt said he recognized for several years the importance that social networking could play for Google. But he and the company failed to act.

"I was busy," Schmidt said.