text: An exclamation mark is not a valid character for an e-mail address extension (or web address) so it wouldn't be possible to add it - that's just how it is, just like it's not possible for me to upload a picture into this answer - someone created the protocols and we're bound by them.\n\nYou can have (!) in the first part of an e-mail address but not in the part that comes after the dot -  xyz!!!@yahoo.com is acceptable but xyz@yahoo.com! isn't.\n\nI'm guessing that somewhere along the line someone has mistyped your e-mail address or has perhaps copied and pasted it but inadvertently included an exclamation mark.\n\nMany people on seeing xyz@yahoo.ca! would realize it should be xyz@yahoo.ca and correct the error themselves but I'd suggest you e-mail those people who you suspect may have your e-mail address incorrectly and advise them of the error.\n\nJust to clarify, this service is something provided by Yahoo which is available for anyone to ask and answer questions on.  It's not a facility for contacting Yahoo themselves - just clarifying in case you had hoped to get a response from Yahoo staff.