Basically, they are just pulling info out of the cookie that is stored for the user. The head section is built in to the code for ezboard. I suppose the purpose is to pull out cookie vars. For more info,
check here for using the cookie variable.
On a side note, I refuse to ever join an EZBoard forum. To me it is a privacy issue since they require, name, email address, address, city, state, zip, dob and sex. This is info that should be and on most boards is optional. I don't really have much to hide but I refuse to give out this much info if I don't have to.