We’ve written about App.net a few times recently: it’s the new “real-time social feed without the ads” launched by former Imeem boss Dalton Caldwell as an alternative to Twitter. Now he’s provided a couple of stats showing its early traction: 250k posts so far from its 17.5k user accounts – all early backers of the site when it raised $800k through crowdfunding. Caldwell says that around half the posts have come from external clients, showing App.net‘s open nature at a time when Twitter is placing more restrictions on external apps in its ecosystem. We’ve yet to see music artists do much with App.net, but we expect to see some early adopters on there soon. The milestones came as App.net got its first iPhone app, AppNet Rhino, hot on the heels of Android app Hooha for App.net.