Every time I&#x27;ve tried to use that feature, the email field in the registration form I&#x27;m trying to fill out rejects it because they don&#x27;t like + in an email address. There are a lot of not-quite-correct email form validation routines out there. Or maybe this is selection bias: the forms where I&#x27;m most likely to want to use the + are with the companies that are most likely to want to resell my email address, and they may be intentionally rejecting the +.