Are LEGO Clikits elements in some way compatible with the LEGO brick system?
According to this review on The Brick Blogger, yes, BUT...
After watching this video by Maniac4Bricks, it seems the compatibility is very limited.
Also the frames are to some extent compatible. The entire frame is 9 studs wide, the little holes align with studs. I've seen this frame used in a GBC module.