the data that is associated with a registered user of this website is purely used for its proper operation. apart from normal webserver logging no further usage of that data is being made.
this implies that there is no need to specify your real name when registering. any (non-empty) name will do. although not encouraged, it is explicitly allowed.
as the act of registration does not provide you with any additional privileges (apart from being able to manage your name and password), there is probably no reason to do so if you don't plan to get in touch with the webmaster to gain additional rights.
unregistering an account will permanently remove the associated data from the database and with that also any additionally held privileges. however, there is no attempt made to remove the traces from the webserver logfiles.