Just a suggestion but I find it very useful when you can tell when other users are currently online.

This is an example of a forum that uses it:

Look at a specific persons post and you can see the green dot at the bottom left if they are online, or the grey dot if they are not online:



An example of how this could be used is, lets say you're purchasing a vehicle/part off of a member and you want to shoot him/her a PM, if you know hes online you can wait for a response but if you know hes off line you can PM him, get on with your day and then come back.

Just a thought. -Eric