so basicaly this about whether web shield checks websites for suspicious code (some AVs can do that) so it can spot unknown baddies…or if it just compares with a database of known sites & known baddies or something
cause if it aint got heuristics then it can be safely disabled to free up more RAM 
I google it up but got no answer so if anyone here know how it works then maybe they can shed some light on this
I refer you back to for first topic (where all of this should have been) as this just causes duplication for those trying to help. http://forum.avast.com/index.php?topic=121741.0
The web shield is possibly the most important of all of the shields as it seeks to prevent malware entering the system.
is it useful against Zero-day stuff?
Very as it can detect hacked sites and it doesn’t get much more pro-active than that, as I have said RAM is cheap, security isn’t.
actually RAM is expensive in EU but for security I aint got any precious stuff I use my PC mostly for surfing & playing, I just wanna avoid having to rollback to a backup (I make a backup image of my system partition regularly so I can restore if something go wrong )