Three months after it opened its platform to outside developers, Facebook is taking steps to prevent some third-party applications from engaging in what the social networking company considers inappropriate actions.

Dave Morin, Facebook's senior platform manager, outlined late Monday in an official blog posting a series of changes in the capabilities it makes available to external developers.

In the blog posting, titled "Change is Coming," Morin states that the changes are designed to create an environment in which the popularity of applications is determined by how useful and entertaining they are.

For example, Facebook wants to stop developers from displaying big boxes in profiles that scream in capital letters messages like "ADD THIS APPLICATION!" to visitors, while hiding them from profile owners.

To that end, the latest release of the Facebook Markup Language -- version 1.1 -- changes how profile boxes display content, removing applications' ability to display profile content to visitors and hide it from profile owners.

"We did this so that the user is always aware of how they are expressing themselves to their friends through your application. This means no more yellow boxes that display 'Add this app!' in the profile box without the user knowing about it," Morin wrote. "We think this will help users make more informed decisions about the profile boxes they choose."

Meanwhile, this week, Facebook will shift how it measures application popularity in its applications directory away from total users and toward user engagement. "This will help inform users as they make decisions on which applications to add," Morin wrote.

The company will also remove email from a notifications capability for developers to contact users who have adopted their applications. The reason is to crack down on what Facebook considers the spamming of deceptive and misleading notifications to its members.

Earlier this month, Morin posted a blog item about this problem, stating that Facebook had noticed developers misleading users "into clicking on links, adding applications and taking actions."

Facebook didn't immediately respond to a request seeking comment.