Slide was not too happy when Facebook temporarily pulled one of its most popular applications, Top Friends, from the social networking site for exposing too much profile information to people who were not friends.

Ahead of today’s F8 developer conference, I asked Slide CEO Max Levchin what Facebook could do to make developers’ lives easier. Not surprisingly, he’d like to see clearer rules about what is and is not allowed, as well as more formal, contractual partnerships between Facebook and app developers. (Facebook is expected to announce a tiered partner system today, and Slide may not qualify as one of the “preferred” partners because of the issues that led to Facebook’s police action).

Slide’s VP of Strategy, Keith Rabois, goes even further. He warns that if Facebook keeps shifting the foundation on top of which app companies are built it will threaten their viability. This might all sound like sour grapes, but coming from the biggest provider of apps on Facebook it does carry some weight.

Levchin, who was one the co-foudners of PayPal, also thinks tha