Pretend my PIN is 1234. I should be able to send mail to email@example.com and have it come out here. Oh no, a clever client knows it can't be right to have a + in the middle of an address, so I just get 'you have entered an incorrect email address' and that's the end of the game. TPC fax addresses aren't welcome either, though they are admittedly very ugly. An example would be firstname.lastname@example.org but without one of the fours. Xtra's wap client hates it.