Why is there an 'About me' panel?
When I go to System -> Preferences -> About me, I am able to give all sorts of informations, like my name, my e-mail address, an avatar, et cætera.
What is it made for?
Solution 1:
If you change your login screen to list users instead of making you type in your username, it'll show the avatar you set next to your name. It'll also show your real name instead of your username if you set it in there. I think this real-name-versus-username thing also affects the Me Menu (at least, it affected the equivalent applet a few releases ago...). As ayan4m1 mentioned, you can change your password there, too. Finally, I think some of this data is auto-filled-in in your Evolution address book if you set it here.
Solution 2:
It seems there are several ubuntu brainstorms on this subject. About Me is a simple way to store a bunch of common personal information. It is part of GNOME. Some people no doubt use it in hopes that if their laptop is lost, someone may use the information to contact them. I believe it also allows users to change their password, which is essential if they are not an administrator and do not have access to the Users and Groups control panel item. As far as I can tell, no applications have programmatic access to the information fields in About Me.
Solution 3:
There was a plan to simplify the About Me window so that it would only be used by the Me Menu, but I don't know what happened to it.