Im starting a auto forum on one of my main websites. The only question i have is, where should i install the forum to? forum.website.com or website.com/forum/? which way would be better and why?
I would install at website.com/forum and maybe create a subdomain redirect for the forum.site.com, so you can use either. Installing in a subdirectory under the root and linking it as such makes for easier relative linking to images or other content on the main site, IMO.
You could do it either way my preference is after, but others have experienced success with ranking using the keyword before the domain.
What I would do is create a subdomain (forum.website.com) for easier FTP uploading. Then I would redirect it to website.com/forum (which looks better, in my opinion). If you don't redirect it, users can access your forum through both URL's. Having two possible URL's per page isn't recommended if you want to optimize the site for search engines.
What the other guys said, plus: if you want a free forum script, I really recommend SMF (Simple Forum Machines). It may not have as many "fun" options as PhpBB let's say, but it has better security. Also you could try Tiny Portal (SMF based). This way you can have a forum AND a news site all in one place.
Go for website.com/forum But, I have read an article in some SEO. That all blogs, forums must be installed in root domain to gain maximum exposure. I do not how far it is true