This is something I sort of stumbled upon. Each user is associated with a number given to them by Wikia. If my theory is correct, there is a direct correlation between your number and when you joined Wikia.
For instance, my Wikicities User ID is 24751354. Therefore, I suspect that I am the 24,751,354th user to join Wikia. I made a page about this on the experimental wiki, thinking that the fancy techies would have code-names for each other, but now I'm just posting them here so I have a place for them.
This is a list of the IDs of all users on our Special:ListUsers.
|Luster the rainwing||11995670|
|Wisps and Spirals||25489209|