There are two ways application developers are breaking the rules to get new users. The first: When a user looks at an application on his/her profile the application can show something different than when other users view the profile. So a user adds an application that looks nice to them. But everyone else sees, say, a big yellow box with an advertisement that says the user wants you to add this application, too.

The second and more devious scheme is being used by many of the largest application developers. They all involve some sort of notification fraud. Generally, you add an application. Then, every one of your contacts is notified that you’ve “written on their wall” or “have asked them a question,” even though you never did. To view the content the contact must add the application. They then find out there is no wall comment, or its a canned question like “is it ok to kiss on the first date?”

via aatw