There is a Facebook group Called CrazyHD .Everyday new member asked for invitation cause it is the biggest torrent site in BD. You can invite them by using their email from Facebook group.
BUT REMEMBER THAT I PERSON CAN ONLY HAVE ONE ACCOUNT. SO When you are going to invite someone just make sure that the person has no previous account.
There is no personal benefit for invitation. But if you invite someone it will make the crazyHD family more strong . Cause the new member will upload new torrent or will download torrent file . As a result it will increase someones upload . Isn't it good for everyone
So lets make the CrazyHD family much bigger by inviting people.