Just stumbled upon this problem for when someone wants to leave a comment and include a value in the URL field.
So long as "http://" is included in the string, the URL is properly established.
HOWEVER, if one simply enters, say -- "www.somewhere.com" problems occur:
the URL entered is added to a relative URL (my MT site IP address) that includes the "cgi-bin/mt/" which is obviously created an invalid link. My anticipate result was that mt would realize it's an external link and add the 'http://' value automatically.
Anyway to fix this so no relative link is created by accident and only an external url is created? I definitely would assume a lot of my site visitors are not privy to HTML code and will not include the 'http' reference.
I hope I don't have to manually correct links not defined fully that are missing the 'http' reference since this could become an arduous task.