Because of past problems with spammers creating bogus accounts - a problem every online forum has to deal with - new accounts must be approved by an administrator before they become active. When you register, an email notification is sent to us, and we review the account looking for signs that it's legitimate. This means that there is often a delay after you register before you can post messages or use any of the features of the site. This kills spontaneity since a person cannot sign up and immediately post a message, but you can blame the bad guys for that.
Every so often, spam accounts still get past us because we err on the side of the new member when there is doubt about the validity of a new registration. Because of that, we occasionally prune zero-post accounts to get rid of ones that got in by our mistake. For that reason, new site members should post at least one message so that we know you're a real person. A hello topic in the "Introductions" folder is best, but a reply in any topic will also do, as we just want something on the posts count in your profile. Accounts with at least one post are never deleted.
Lastly, we have a link to the forum rules at the beginning of every folder. Read them, because they are enforced - even the ones that people think are silly.