If both you and the person who answered your question are registered users, you can use the message board. Go the person's profile page and click on the envelope icon by their name in the header. That will take you to your own message board, but with the other person's ID already filled in. Complete your message and hit "Send". If either of you is not registered, you can use the discussion comment section and hope the person who answered sees your comment. The site's Supervisors review most comments and we see a lot of "Thank you"-type comments. We have also seen "that doesn't help at all." Foul, nasty and nonsensical comments get deleted.