i dont think they will.
After all, msn and yahoo do same dont they?
Not quite...Msn and Yahoo both have limitations. Msn has rules on what type of files you can send, it also has limits on the size of the file. Yahoo isn't as bad, you can send any file type you want without changing something on it like you would have to do with Msn. Yahoo also has a file size limit, just can't remember what it was.
Besides, who in their right mind would try and sue or shut down Google? They are slowly taking over the world.
The only thing I belive that may happen, is that Google may adapt some rules on the file sharing part of their program. Though, I don't see it happening any time soon. The RIAA and MPAA have bigger fish to fry.