http://www.standalone.hyperlink.com http:/one-slash-only.absolute.path [ http://example.com ] ( http://example.com ) < http://example.com > http://[1080:0:0:0:8:800:200C:417A]/IPv6address.html http://[3ffe:2a00:100:7031::1] (the final "]" is ambiguous in text) http://[3ffe:2a00:100:7031::1]/ mailto:someone@somewhere.com news:comp.lang.python An email address in a sentence: someone@somewhere.com . ftp://ends.with.a.period . ( a.question.mark@end ?)