It seems that whatever bulletin board program you're using is the same one that's being used by Themes4BB & others. That's actually great and makes it very easy to navigate both forums.
I did notice though, that Themes4BB has an option to add your thanks to any message by clicking "thanks" at the bottom of a message. It takes much less time to thank someone so there are probably more people showing appreciation than would bother adding a "thanks" message.
Another benefit is that it results in less clutter and makes it very easy to thank someone. A big benefit is that if you're following (or subscribing to) a thread. You're not wasting your time checking for an update to a thread that's just a "thanks".
I still occasionally send a message wth thanks when I have something to say.
"Thanks"
