Short, concise description of the idea
Add "last logged on" or "last seen" to the user info page.
Full description of the idea
On the full user info page, we can see when a user last updated his or her journal. I think it would be neat to see when the LJ servers last saw that user log on. A "Last seen: " field on the user info page would be updated every time a user viewed a page (static or journal) on LJ. Obviously, this would have to be a feature privacy-concerned people could switch off.
An ordered list of benefits
An ordered list of problems/issues involved
An organized list, or a few short paragraphs detailing suggestions for implementation