Google has signed on MySpace, the world's largest social network, to its platform allowing outside software developers to write programs for social Web sites, the companies said on Thursday.

The addition of MySpace gives the Google platform greater strength against fast-growing Facebook, which opened up its site to developers in May and has seen its user base grow to more than 48 million people since then.

Google unveiled its OpenSocial platform earlier this week, saying it would give outside developers tools to write programs for any of its social network partners.

This will eliminate the need for small start-ups or even one-person shops to customize their programs for each site.

Google and MySpace said they had been working together on the project for more than a year. MySpace has some 110 million users worldwide.

Google had already disclosed that social networks such as LinkedIn and Friendster joined the program as well as some of the biggest independent developers on Facebook.

Google lost out to rival Microsoft last week, when the software maker took a minority investment position in privately held Facebook and shored up its position as the site's advertising delivery partner. The deal valued Facebook at $15 billion.