Yes if you do a simple URL of URL tag followed by URL followed by closing tag it works, but that mean what you see as the link is the link itself, as opposed to using the URL option tag where you have URL="hyperlink" followed by the friendly words that you want to appear (as opposed to having the link itself appear).
What I mean is a difference between this:
http://www.caymanclub.net and this:
Best Cayman Site on the Web!
The first example works in Reviewpost, but 2nd does not.