Gaffer:
Do you really run into so many players or GMs that are so bad that you need a list to remember them for YEARS?!
On a site where you routinely interact with someone for weeks or months with both of you using aliases the whole time, yes.
I remember that Gragnar the Distruptive was a real piece of work but I'm never going to remember who was playing him.
And since everyone gravitates towards certain systems you will constantly have the same players applying for the same games, it would be nice to know that that "this guy here with an asterisk" was someone you marked as an enemy.