res3: Option[String] = Some(theon.github,com)
Uri.parse("http://theon.github,com/scala-uri?param1=1¶m2=2").host res3: Option[String] = Some(theon.github,com)
ah, yeah. Wikipedia agrees at the least.
"The Internet standards (Requests for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters 'a' through 'z' (in a case-insensitive manner), the digits '0' through '9', and the hyphen ('-'). The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted." http://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names