in reply to
Marking nodes as solved?
I like this idea.
I think it's also a question of netiquette.
Besides it's nice to read something like "thanks, your answer works" this would also help others searching for answers to the same problem.
So, I'd propose adding a suggestion to the faq, that the OP should also post if and what solution works.
Possibly a netiquette section in the faq with more information would also be useful.