Even a simple single page website can be used for business purposes. You will have to work harder at getting the site indexed by the search engines and will need to get plenty of back links to it to be sure it gets noticed and listed.
But on the positive side you can really target in on your desired keywords and make the site a target for a very focussed niche audience.
With less content the site needs to highlight and focus the attention on one or two primary keywords to get it listed in a prominent position in the search engine results pages.
