The main point is that this is a help forum. If we help people over IM or PM, then no one else gets to see the solution and process, making it only helpful for one user.
If it is posted online, anyone can find it through searching, and it can help hundreds.
It is also much easier for us who are helping.
I do like the idea of a suggestion box though, but we can just use PM to admin, chillout room, etc.