Yes i think its a good idea. Some will get the idea how many people liked his thread.
But if there is a liked button then there must be a dislike button.
this is not youtube

but if we need something better socialcomunity then
http://in-galaxy.com/ join here
I think we need a
thanks button for avoid the spam posts like : +1 , thank, etc.... It would be a nice feature in the new forum software.