Walters later sent a follow-up e-mail to Jonathan Wald, advising him not to bother following up with the college graduate, since she did not have an appropriate U.S. visa.

CNN: Syria's U.N. ambassador rips criticism of his daughter

"The only piece of information you see is the information you already know - that might be a Facebook name, a Twitter id or e-mail address, " says Jonathan Grubin, head of Send Social.

BBC: Real life postage that just needs your e-mail address