Advertising opportunities are getting better on social networks, not worse, according to Google co-founder Sergey Brin.

"In general, it's been improving but we still have a long way to go," Brin told reporters at a conference in Jerusalem to mark Israel's 60th anniversary. "People are expecting overnight to wake up to a miracle... but these things take time."

Brin's words come at a difficult time for social networks like MySpace and Facebook. For the past few months, Google, which serves ads on MySpace, has been critical of the site's traffic, pointing out that users seem less interested in ads than many had predicted. Recently, MySpace took some heat from corporate parent News Corp., which chided the social network for missing revenue projections. And yesterday it was reported that ad sales were expected to slow across the board.