Why can I not add a url to an answer?

Trying to provide answers to a couple posts I found that I can not include a link/url in the body of the reply or my answer is simply not posted. I received no notification that this was the case. It just did not show up. It is kind of frustrating to try and guess what happened.

It would seem that Q&A would be more usefull if you can point someone to an example but if not, I would like to suggest that...

A) there be some kind of notification telling posters ahead of time that they can not use links in their posts, or

B) at least notify them when they post with a link that their answer will not get posted.