The URL is clickable, but the forum has implemented a security feature that will display links to the bitcointalk forum as green when the user hovers their mouse over the link, and will display as blue for all other links.
That "green" is barely noticeable on my screen, and I bet I'm not alone.
I am aware of the feature and notice it. The feature may not be all that well known.
I'm wondering why the security feature that stops fake links to be labeled "Bitcointalk.org" didn't kick in. Example:
http://google.com[url=google.com]bitc ointalk.org[/url]
Converting the text to upper case answers it: BITCOINTALK.O
ГG.
google.com
It seems that using the above BB code will result in "google.com" to be displayed, however it will show as "bitcointalk.org" when previewing the post.
http://google.com