But that's why a like button would be helpful. It's common courtesy to thank someone for help and a like button would at least curb people just littering threads with pleasantries.
It is an option, but I have my reservations about it.
What real purpose would a 'like feature' serve, to show how many people appreciated your contribution who may not have any smerits to give at the time?
If there's no means to earn the likes would it not turn out to be an unnecessary metric that would be giving at the slightest whim without careful consideration? Users earn merits and by extension smerits, so they would try to be very careful in giving them out, likes on the other hand would be easily overused.
Creating a system where likes are earned (sort of like the bump system) is an alternative, but not sure if it's worth the stress for the admin.
Well, it's pretty self explanatory really. A thanks button is just that - a way to show appreciation. Not much different than merit really but that is in very limited supply and newbies have little to none of it. It's obviously not essential but would help in situations like the OP and implementation of it should be easy given it'd be like the merit system. 'Overusing' the likes shouldn't matter either because what are the consequences of doing that?