Not with them concurrently running. Only 6 active apps can be run at the same time (unless the app registers itself as a service, which a few of the IM ones do). Beyond that, if your system starts running low on resources, android will decide what you need or not by randomly closing some down. This was overly apparent on the G1 hardware.

Now, you can switch back and forth between more than that, and for the most part not notice anything because of the saved state that it does when the app closes down.. but having more than 6 different apps constantly communicating or sending updates through the network or to the user.. is impossible for android AFAIK.

Again, I'm excluding services.