Ad.ly announced today that it has launched its in-stream monetization platform for apps and websites. This means that apps or sites that publish streams from any source (like Twitter, Facebook, MySpace, LinkedIn, etc.) can use Ad.ly’s API to serve contextually and locally targeted ads based on streams they are reading and where they’re located. The platform is called Ad.ly for Apps.

"Apps are key constituents in the stream ecosystem, yet they have very limited options for monetizing their streams. At the same time the inventory they represent is very attractive to our current base of marketers," says Ad.ly CEO Arnie Gullov-Singh. "We built Ad.ly for Apps to connect the dots and help both apps and marketers create more value out of the stream."

Apps and sites can join Ad.ly’s network by going to its developer page. "Once approved, these applications and websites can implement the Ad.ly for Apps API, which take as its input the contents of the stream and returns one or more targeted in-stream ads, which the app can stylize and display adjacent the given stream," the company says. "The Ad.ly for Apps API is flexible in that it works with any stream on any application on any platform, enabling applications and websites to monetize all their available stream inventory."

First Ad.ly is launching the product with its existing advertisers and partners, but they’ll be adding a self-service buying interface for advertisers in the coming weeks.

Earlier this month, Ad.ly announced a partnership with MySpace.