Some of the people who develop applications for Facebook are upset with the online social networking site.

The reason: Facebook plans to charge developers for the process of verifying that the apps actually work on the site. For its part, Facebook says the process is meant to increase a user's trust of apps that are posted on the site.

It's also supposed to help developers who want to build a business around their software products to have more visibility on the site. But some developers speaking out on a forum on the Facebook site are upset.

They say the fact that the fee would be charged each year may shut out smaller developers who don't have the money to make payments annually.