To be blunt, I want to make a custom bbcode, but am unsure if it would present a security risk to my forum. I realize that html on phpBB3 in it's vanilla form is dangerous, but since this code is more specific, I would think it would be impossible for a hacker to take advantage of this specific tag.
The bbcode would probably be: [shout][/shout]
The html equivalent: <iframe title="NAMEHERE" src="http://www.shoutmix.com/?NAMEHERE
" frameborder="0" width="150" height="400"></iframe>
Before you say that all functionality for html was stripped from phpBB3, I have tried this using BBcodes and it worked fine.