Web giants announce further integration with social networking sites.

Yahoo has announced that its sites will be accessible through Facebook Connect from next year, while from today all sites using Google Friend Connect can be accessed through users' Twitter logins.

The new integration shows a growing recognition by Yahoo and Google of the social networking sites' huge popularity.Jim Stoneham, vice president of Communities for Yahoo, said that the extended integration is a continuation of the company's strategy to make its sites more open, social and personally relevant.

Facebook Connect allows the site's 350 million users to login to other web sites using their social networking ID.

"With this integration, we are opening the door for two of the internet's largest online communities to make it easier for people to stay connected," Stoneman said.

The sites include Yahoo Mail, News, Sports and Finance.

Yahoo chief executive Carol Bartz spoke in March of Yahoo's intention to partner with social networking sites, including YouTube, Twitter, Facebook and Skype, to provide a seamless experience when users move from Yahoo to more social places.

Until now the integration between Yahoo and Facebook allowed Facebook users to access their profiles and update their status from the Yahoo homepage.

The Google announcement will mean that its nine million Google Friend Connect users will be automatically connected to their Twitter profile and contacts once they have signed in.

Google users will be able to invite friends via Twitter and tweet when they have become a member of a Google site.

Friend Connect allows developers to add social features to their web sites.