Markus Weichselbaum, CEO of social application developer, says he has yet to see interoperability advantages from OpenSocial, Google’s common API for social networking applications.

Speaking at MySpace Australia’s developer platform launch in Sydney last night, Weichselbaum said his company needs to target each social network individually due to differing demographics and methods of application development implementation.

“From our perspective there actually isn’t much overlap in terms of users. A user may over the lifetime of using social networks, go back and forth [between networks]. But they’re not actually using the same application on [different] social networks,” he said. claims to have 12.5 million users and over 28 social networking applications.

Allen Hurff, MySpace engineering senior vice president, told Builder AU that MySpace has implemented a majority of OpenSocial’s 0.7 API but has also extended the application platform to include functionality such as bulletins and the ability to use Actionscript.

Weichselbaum cited MySpace’s extensions as a cause for MySpace specific implementations.

“Things that are very specific to MySpace and make sense on MySpace, the particular extensions to the OpenSocial API — they don’t make sense on Hi5 so much and, actually, what you can do on these networks is different.

“Different platforms are going to be a fact, they are all very specific for what they are trying to achieve. As a developer we take that in our stride. It would be nice if there was one language,” he added.

At its launch OpenSocial touted interoperabilty as being one of its key features.

Hurff remains adamant that MySpace is improving the OpenSocial platform rather than fracturing it.

“[We have] extended the platform, not splintered it,” Hurff said.