I would recommend against using vBulletin this way. It is very confusing to the visitor.
For instance, when I load httpme's website, I see a forum. Well I am not looking for a forum, I am looking for a hosting company. Click -- gone.
Using a forum requires me to set aside my preconceived notions (humans are creatures of habit, so it's not smart to expect them to work to just look at your basic offerings -- they're not going to) of what forums are and now click around to try to figure out where the info I want, resides. I have to work to figure out how the site is organized and I have to try to ferret out the most basic information. Click -- gone.
Forums are best used for forums. Forum software has a purpose and it does a great job at what it is meant to do.
If you are trying to sell something, I strongly recommend against using forum software to do it. Use the right tool for the job. Use the right site format for the goals you are trying to achieve. Don't force your customers to do mental gymnastics just to find the most basic information about your product.
As for how vBulletin works, your questions belong over at vBulletin.com and their forums are chock-full of every detail you could conceivably want to know about.
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