The spec currently says "2.Any Identifier that contains the character '@' in any other position other than the first position must be treated as an e-mail address." About this, Yaron Goland wrote:
This seems dangerous to me since @ is a perfectly legal character in a URL including the HTTP URL. I wonder if we should say that we know how to specifically handle e-mail URLs and provide the parsing rules there. This would come straight out of RFC 6068. In other words we can call out mailto URLs for special treatment.
Is he right here/