When Social Times interviewed Ad.ly CEO Sean Rad just three months ago, he responded, “Not at the moment,” to our question about whether Ad.ly had plans to expand their in-stream advertising scheme to social networks other than Twitter. It appears this must be the moment, with the announcement today of a deal to integrate Ad.ly’s platform into MySpace.

The deal creates the potential for the millions of MySpace’s top users, including social influencers, celebrities, filmmakers and musicians, to monetize their activity via the MySpace stream. Ad.ly advertisers are now able to choose to have their ads sent through Twitter accounts into the Twitter stream, through MySpace accounts into the MySpace stream or through both accounts depending on their campaign goals.

Marketers select users for their advertising campaigns from enrolled Ad.ly content creators, who receive a request to participate in the campaign citing how much they will be compensated if they consent to having the ad pushed to their friends. Publishers can decide which messages from advertisers they want to support and Ad.ly delivers the approved messages into their activity stream.

“MySpace pioneered tools for musicians and now with this new relationship with Ad.ly we’re doing the same for our community of social leaders – allowing monetization of the activity stream,” said Sean Percival, Director of Content Socialization for MySpace. “This deal provides publishers with the opportunity to associate themselves with brands that represent and reflect their personas online.”

“We’re excited to enable MySpace’s most influential users to monetize their audiences by bringing them onto our in-stream advertising platform and connecting them with our stable of top-tier advertisers,” said Derek Rey, Vice President of Sales for Ad.ly. “Adding MySpace’s stream as a new channel on Ad.ly considerably extends the reach of our network making it even more compelling for advertisers looking to be part of the broader stream ecosystem.”

According to a press release from MySpace, users may enroll beginning today.