I recently downloaded 11.10 and demoed on the Live CD. Snapping worked great.
After installing snapping no longer works. I tried recreating my home directory from /etc/skel as well as creating a new user to make sure it wasn't a local problem. No luck. I also tried reinstalling which didn't help. Nor did installing all compiz-plugins* and wmctrl packages and reloading Compiz.
Edit – 1: I installed CompizConfig Settings Manager but nothing jumped out at me to change.
What might have changed between the LiveCD and the installation?
Edit – 2: After continuing to look for a solution I've realized my terms don't mean what I meant them to. By snapping I mean the feature termed Aerosnap in MS Windows where dragging a window to the left/right/top of desktop will cause the window to be sized to fill the left half/right half/all of the screen.
Edit:This install is running on a Dell E6420 with a nVidia Corporation GF108 [Quadro NVS 4200M] Video card. I am selecting "Ubuntu" on the login screen but end up with unity-2d-panel and unity-2d-launcher processes running upon login.
Best Answer
After learning that Ubuntu was running Unity 2D I started suspecting that there was a problem with my video drivers.
I purged nvidia-current* and nvidia-settings* packages and rebooted (turns out logging off and on again is all that is necessary).
Logging in again the "aerosnapping" now works so I'd consider this answered.
Now to figure out how to get these drivers correctly installed.