I noticed in several of the emails that I got today from the forums that the links are broken.
I am using Outlook 2007.
The problem is that the bbcode formatting is included raw in the email that is sent so it is surrounded with bracket LINK bracket tag.
The problem occurs in Outlook 2007 because it can't tell where the link finishes and the LINK close tag begins so [/LINK is included on the end of each of the links.
I don't think that many email programs out there will support bbcode so it would probably be a good solution if you preprocessed the reply before email and stripped out the tags.