Move your mouse pointer over the username link (underlined)
There should be a status bar at the bottom of the page that will identify the link you are pointing to. In that line you will see the userid=xxxxxxx information you are looking for.
If not, at the top of the page click on 'view' and then click on 'status bar' to enable it.
This is how it works with internet explorer. If that's not what you're using someone else may have to help you.
regards, Marc (userid=16)