This is the nickname that Crisses use for signing pages.
Back in the arcade days, you could only record a 3-letter high score. No, we didn't have XES as our moniker at the time, but it amuses us that we can actually say our name in 3 letters. So why not?
We also use XES on the PmWiki project. So you can go there, view our profile, see the contributions we've made, etc.
Sometimes we also sign site updates with our longer name and put Crisses New in the author box :P