Yeap, basically everytime someone posts the message goes back to the top of the list of posts and more people see those at the top.
If a post is not getting replies and is in danger of being lost down the list you can give it a bump to the top just by posting. Personally I do it if I spot one that is over 24 hours and has had no replies and I use the
smiley.
Some forums object to this being done and moderators tell you off for doing it. Here though we think it's all just part of helping each other to get answers and the moderators will join in giving bumps if it's needed.