Technically it lets you reserve your username and upload contact phone numbers (really needs to use hashes or something). When this happens your contacts will s

Technically it lets you reserve your username and upload contact phone numbers (really needs to use hashes or something). When this happens your contacts will see you are wanting an invite and can let you in. I could be mistaken on exact functionality but I did this and was in within a couple of hours no problem. So technically it isn't useless and has real functionality, just not super useful till you get the invite.