Mastercoin initially did fundraising through 1EXoDusjGwvnjZUyKkxZ4UHEf77z6A5S4P. It now seems to be used in every Mastercoin transaction (it has been used in thousands of transactions).
Why is the address still being used in every mastercoin transaction? Is this built into the protocol somehow? I suppose it could be a spam prevention mechanism, but I would think the bitcoin transaction fee already prevents spam.