I agree, I haven't seen the "Wait in line for a free account" before. Can you describe this feature in more detail? For example, how long does a user have to wait, does it allow in more users as the size of the queue grows, etc.?
It is usually set to a fixed number of users per hour with a minimum wait time. Keeps the server happy when I get HN'd/Reddit'd/etc. (Does anybody get Slashdotted anymore?)
Thanks. I've signed up for a couple of services that do that. It seems to work out even though some people get a little annoyed that they have to wait.