Okay, here's a video from a member of the phpBB community about XSS vulnerabilities and why they are so serious.
http://www.vimeo.com/6952783
This video was created by SneakySimian, who also happens to be on this very site. Many thanks to him for the informative video!
XSS and what it can do
Re: XSS and what it can do
He is also a former support team leader of phpBB. 
Re: XSS and what it can do
I watched it after it got reported on phpBB weekly.
It definitely a very enjoyable and I learned some new stuff about XSS from it. Turns out to be far more dangerous than I initially thought. Really nice.
It definitely a very enjoyable and I learned some new stuff about XSS from it. Turns out to be far more dangerous than I initially thought. Really nice.