Wikipedia is not known for being well vetted. When I went back to school not all that long ago, Wikipedia was the one NAMED site that we were not allowed to reference in any term papers for that very reason. Just about anyone can post in Wikipedia and what they post as fact can be completely wrong with no vetting at all. The article that you posted appears to be accurate but is far from complete. It doesn't list any of the issues with using some of these characters like the ampersand, the back tick, the forward or backslash, and other characters that have real power on the OS command line and are simply filtered out by many systems in a world where attacks on them are the norm. It also doesn't talk about the funky and sometimes confusing formatting required to use many of them. It shows the ampersand being used with no problem but as we have seen here, that is not always the way it goes. In a world of constant system attacks and the need to increase security to block them, you will find that despite RFC2821 and RFC2822, many systems will block or filter out many of these "special" characters allowed by these RFC's which will limit or prevent the use of email addresses that contain them. This type of discussion can quickly turn into a pissing contest so before that has the chance of happening, I will end my part in it now