App.net is going freemium; CEO Dalton Caldwell has announced that starting today, paid users can help expand the social network's reach by distributing invites granting free access to new signups. In a blog post announcing the new measure, Caldwell says his team has been researching a way to offer free accounts from the start — echoing what he told The Verge last month. He cites Dropbox and Github as just two examples of companies that've reached a massive audience (while maintaining their popularity with users) thanks to the freemium approach. Until this point, App.net has demanded an annual $36 fee to register with the Facebook / Twitter alternative. Caldwell says launching as a paid service enabled App.net to develop a community of passionate users and a sizable ecosystem of third-party apps.

There are some limits that come with the free tier, however: you're limited to following 40 people, and will also need to make due with 500MB of storage. Thankfully the latter can be increased if you continue the chain and invite others to join; 100MB will be awarded to both users so long as the invitee follows five accounts and authorizes a third-party app like Netbot.