I have a site with forums. The forums are currently at forums.example.com (a subdomain). I've heard that for SEO and usability in general it's better to have them at example.com/forums. Regarding security and maintainability, however, it would be better to host the forums in a seperate VirtualHost (or to be exact, a seperate cPanel account).
Is this even possible, should I want to do this?
VirtualHosts are distinguished by hostname, so if the forums were at example.com/forums then they'd be served by the same VirtualHost as everything else in example.com.
Personally I'd go with the subdomain - it's straightforward to set up and provides some degree of isolation if something goes wrong. The SEO aspect is fairly off-topic for Server Fault, but I'd imagine the actual content of the forums would be of more relevance to rankings than where the word 'forums' appears in the URL ;)
I've heard that for SEO and usability in general it's better to have them at example.com/forums.
I disagree. It shouldn't make a signficant difference.
Regarding security and maintainability, however, it would be better to host the forums in a seperate VirtualHost (or to be exact, a seperate cPanel account).
Yes; and quite apart from server-side security issues, there's also the client side. If you put your forums on the same hostname as the rest of your site, any cross-site-scripting vulnerabilities in the forum software (and there are almost always cross-site-scripting vulnerabilities in forum software) immediately become cross-site-scripting vulnernabilities for your main site. If you've got anything sensitive on that site like accounts or admin pages, your forum has compromised your mission-critical stuff.
So keep your forums on forums.example.com and your main site on www.example.com, where they won't be able to leak each others' cookies.
This is a more complex question regarding url optimization for SEO. I would recommend buying and reading this book:
"The art of SEO" http://www.amazon.com/dp/0596518862/
