MySpace announced today that it has struck a deal with Ad.ly, an ad service that serves in-stream advertisements, known mostly for its Twitter-related efforts. The deal will let content creators across MySpace (including celebrities, filmmakers, musicians and "social influencers") reach their fans and monetize their activity via the MySpace stream and Ad.ly, MySpace says.

"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."

Starting today, MySpace publishers can sign up with Ad.ly and create a profile. Once registered, they can decide which messages from advertisers they want to support, and Ad.ly will deliver the approved messages via the activity stream.

Ad.ly now claims to reach over 50 million unique users on Twitter and MySpace. Advertisers can choose to have their ads sent through Twitter accounts into the Twitter stream or through MySpace accounts into the MySpace stream (or both).