Social media leaders Twitter earned a spot in the PR doghouse last week by alienating a key sector of their audience: developers. What did they do? They changed the rules of usage for third-party developers who create and sell apps that work off the Twitter interface–and number well into the thousands.

The move had been expected for some time, but the new rules will almost certainly make it harder for the producers of some very popular apps to continue using Twitter’s API.

We understand that Twitter wants to retain a certain degree of control over their product and everything that falls within its purvey, but as Matthew Ingram writes in Bloomberg Businessweek, many of the third-party creations now restricted by Twitter actually improve the service and help bring more users aboard.

We’re not developers, so we have to ask: Why did Twitter make this move now, and what can they do–short of reversing these rule changes–to earn their way back into the good graces of the entrepreneurial app community?