Kudos, post voting or similar
Some forums have a box at the bottom of each post for Kudos or "vote up", or thanks.
Given this forum is used heavily for advice, I think something like the above would be a good idea.
Heaps of different ways of doing it, but one way might be:
Each response/post generates "up votes" so the good replies are seen with a tally of thanks by people who read it and found it helpful. You can do down votes for stupid replies or shit-stirers, but that can be pretty negative, so if you don't like it, don't vote it up.
Food for thought