Lol for me http://www. results in “Unknown Tag Type” while http://www works.
In theory it’s a perfectly valid domain:
http protocol, host www and the . in the end should do nothing.
Someone could host a website on this link if he owns the .www tld.
If you can reproduce it you have founda nice little DoS 
URLs are very strange, they seem so simple but are so hard to parse.
http://pc-help.org/obscure.htm