While trying to compete against monolith Twitter, App.net has taken a big step today with the introduction of a freemium tier.

Much like Dropbox and GitHub, users don’t have to pay a fee to use the service. But there is a catch, for now.

Users wanting a free account must snag an invite from a paying member. The free accounts also have some limitations, most notably the ability to only follow a maximum of 40 users. There are also limitations on the amount of file storage and the file upload size.

By offering the free accounts, App.net is hoping to expand its member base that pays $36 per year, or $5 monthly, to use the service.

The new tier should also be a boon for developers of App.net iOS clients. Back in September, Rhino became the first App.net client to hit the App Store. After that, the flood gates began to open.

Our own Christine Chan has done a great job looking at some of the more popular App.net apps. In November, she authored an App Showdown between Netbot, Felix, and Rivr. She declared Felix to be the winner. The pictured Netbot, from the makers of the popular Tweetbot app, has since gone free.

Are you interested in taking a look at App.net now that there is a free option?