I was looking for a simple solution that would show (1) who has logged in, and when, and (2) who has logged out, and when, and (3) who is currently still logged in.
This feature would be very helpful for ensuring that multiple administrators don't accidentally overlap each other when logging in and making admin changes to the site.
Wassup doesn't really provide simple info like this, and in fact, if you log in as an administrator and spend all your time inside the admin and plugin pages, you don't seem to show up as "logged in" at all. The only time a user (or even an administrator) shows up as "logged in" is if they are logged in AND visiting an external site page. Also, if your page goes idle for a few minutes, you no longer show up in the current users tab.
Or am I not using Wassup properly...?