Myspace Email adding

Has anyone had any experience with toying with this? ex: is there a limit per day? I currently do email list adding on facebook but looking to expand... I don't mean train site's either but if you have experience with train sites the results should be the same so if you could what are the limits.

Edit: Accounts are automatically made. Each account will have designated proxy. So just wondering the basic email invitation limits besides the 50 at a time.