It should be invisible to most, but the boards have been hit with a tremendous amount of spam recently. I'm putting a little bit of effort into database cleaning as a result. Staff or volunteer spaminators reject the postings of the spammers, but sometimes we accumulate accounts. (When Michelle and I check for spam, we delete the account that made it, and sometimes ban the IP as well, but I'm not sure if the volunteer mods have the ability to do that.)
In any case -- seems to me that smaller databases are a good thing, in terms of responsiveness, so I'm doing some purging. Foremost, I have deactivated all accounts where an account was created but the system shows no visit to the boards after the account was created. These may have been accounts where an error meant someone never got the e-mail with follow-up steps, or maybe they are duplicate accounts, or whatever -- many of them certainly are obvious spammers (given that their profiles include URLs for cheap drugs, WoW gold, etc.). I will skim through for the oddball where I know they should stay on the system, and then poof, I'm deleting the rest en masse.
So...if you at some point created an account (perhaps several years ago), didn't get around to logging in until now, never posted anything, and your account no longer exists, you know why. Just create a new one.
If I get the chance, I may do further purging, moving on to users who are shown as having visited the boards after account creation, but give other indications of being spammers.