i think its basic courtesy to thank someone for helping you, and if someone wants to take the time to say thank you, i dont see anything pointless in their appreciation or in replying to them. When they take the time to say thank you, it also lets us and anyone reading the thread know the suggestion(s) did in fact resolve their problem.

Considering how often helpers everywhere aren't shown the slightest bit of appreciation and in fact get a lot of rudeness/abuse for their efforts, it brings a smile to my face when anyone says something nice to someone who helped them.

ParaBrat @#mIRCAide DALnet