Embed website in a post.
 

At a board I used to go to which has since been shut down, there was a custom BB code to embed a small window within a post with the website specified in the code.

So, for example, I could use this code for, say, google.com and one could search google from within that post.

Anybody familiar with this modification? Sorry if it doesn't make sense.

It sounds like they are using an i-frame to do this but iirc, this could lead to security issues, not to mention that you have 0 control over what the linked site displays.

If you just want people to be able to do a google search, there are plenty of ways of doing that you'll just need to look around.

Allowing an iframe is at least as risky as enabling HTML on your forums in my opinion, I wouldn't recommend it.