Crowd-sourced social platform App.net has surpassed their goal of raising $500,000 just two days before reaching the end of their campaign thanks to one final push from sponsors. The company currently has nearly 11,000 backers that have donated $700,000+ during the month-long campaign.

Founder and CEO of App.net Dalton Caldwell says he has been disappointed with free Web 2.0 services and was inspired to build a real-time social service where users and developers come first, not advertisers. If you're thinking this sounds a lot like Twitter, you are certainly on the right track.

The key difference is that unlike Twitter which has no clear business model, App.net will be a paid service. Caldwell points out that the customer of an ad-supported business is the advertiser. With a paid service like App.net, the paying member is the customer, not an advertiser. This, he surmises, will make it easier for the company to keep the users happy.

He goes on to lay out some key values that his company will adhere to, such as the fact that they will never be ad supported and their company will be aligned with making the most innovative and fun product they can. Caldwell also notes that his company will be committed to developers, since his team is also constructed of developers.

A $50 donation gets you a year of pre-paid membership service with App.net and the ability to claim you preferred username before the service launches. For $100, you can expect all of the above perks in addition to receiving the entire App.net developer tool kit and finally, a $1,000 donation gives you everything listed above plus a personal meeting with Caldwell in San Francisco.

Do you think a paid version of Twitter can really be successful? On one hand, a paid network would no doubt limit the amount of spam accounts that can be found on Twitter but at the same time, people are generally cheap and don't like to pay for a service that can be had for free elsewhere.