I have people, typically once a day or so, sign up but never come back to authorize their account. One person even signed up twice on the same day but never authorized.
I think the biggest issue is that the emails sometimes end up in the spam filter. I've sent test messages to both Gmail and Hotmail. The Gmail messages made it while the Hotmail messages were sent to the spam folder. It was easy to find, of course, but people don't expect that to happen. I've added a warning to the signup screen but I still get people signing up and then not authorizing.
I don't normally email people who sign up; you can use a throwaway address as far as I'm concerned, meaning you can create an address and use it just to get your confirmation code, authorize your account, and be done. I don't like spam so I don't want you to ever think you're getting spam from here. However, I have emailed the people that signed up but never authorized, asking if they were interested but just never got the code. So far, not one has replied, so I assume that either they're no longer interested, or the email directly from me also got eaten.
So please, if you attempt to register for the site and never get a confirmation code, use the About > Contact Us form to send me an email. I'll authorize your account from my end.
I know having to register might be a bit of a pain, but remember, the videos are free. Registration just lets me track downloads as well as control the forum contents (I don't want any forum spam) and comments on my blog posts (I don't want any blog spam.)