Horribly off-topic, but interesting (at least I think so):
As far as I can tell, "(" is in fact valid. In the URI standard [1], a URI has a `path` which is made up of segments. Each `segment` is a set of pchars delimited by by "/". The `pchar` character class includes the `unreserved` character class which contains the `mark` character class which contains both "(" and ")".
That said, I'd argue that "(" and ")" should never have been allowed because of the tendency for people to mention web sites like this (news.ycombinator.com). I'd also argue that trailing punctuation should be ignored for cases like this news.ycombinator.com.
But oh well, it is too late now. These characters are in URLs and that means they are here to stay.
FYI, rfc3986 is the latest for URI syntax (obsoleting rfc2396), but you're still right, and the grandparent comment is wrong: parentheses are legal in URIs.
News.YC also mishandles '<' '>' around URIs, which is the recommended manner for delimiting them. (Consider, for example, <http://www.example.com>.)
As far as I can tell, "(" is in fact valid. In the URI standard [1], a URI has a `path` which is made up of segments. Each `segment` is a set of pchars delimited by by "/". The `pchar` character class includes the `unreserved` character class which contains the `mark` character class which contains both "(" and ")".
That said, I'd argue that "(" and ")" should never have been allowed because of the tendency for people to mention web sites like this (news.ycombinator.com). I'd also argue that trailing punctuation should be ignored for cases like this news.ycombinator.com.
But oh well, it is too late now. These characters are in URLs and that means they are here to stay.
[1] http://www.ietf.org/rfc/rfc2396.txt