Last year we had a crazy idea to give out tiny free accounts to anyone who wanted one, without even asking for a credit card.
While we got signups from many nice people, we were overrun with people signing up dozens of times, attempts at spamming and abusing our network, and other bad/annoying things. It's also getting difficult to allocate so many IPv4 addresses. We tried hard to fix the problems but just couldn't keep up. We failed, and we're sorry we weren't able to activate you!