As debate rages over whether or not social networks are actually profitable, there has been little doubt that developers could make a cool buck or two with Facebook applications. But now, according to one developer, the potential to create a profit with a widget is dwindling.

An independent study by Facebook developer Jesse Farmer showed that application use dropped three weeks after launch and activity in Facebook's developer forum has slowed since January, with fewer posts and fewer active users. He shared the results on his blog and speculated that less developer activity could only mean fewer new applications developed specifically for Facebook.

"It boils down to this: investing most of your man-hours into Facebook at this point in time is a mistake. The potential return on that investment, a year after launch, is a fraction of what it once was," he wrote.

Meanwhile, other social networks, including MySpace and Bebo, have opened their doors to developers. Google also launched OpenSocial, an initiative to standardize applications across the internet that Facebook has not joined thus far. Farmer believes developers may now be putting their eggs into more than one basket as the Facebook picture becomes cloudier.

"Application companies are branching out to other social networks not because they necessarily show more promise than Facebook, but because the future of the Facebook platform has become murky," Farmer wrote.