This is for brainstorming how we can use app.net. app.net allows 256 characters, which allows a little more flexibility, as well as images and videos (through oEmbed). Actually arbitrary annotations (metadata) can be used, but of course viewers will probably not support more obscure ones.
Another advantage of app.net is that there is currently a significant contingent of early adopters and developers, exactly the people who might be willing to contribute to MediaWiki.
This post was posted by Mattflaschen, but signed as Superm401.