The internet - and web sites - can be used for a number of purposes, but the simplest is as a source of information.
Even for no other reason, some kind of web presence is very useful to be able to refer people to then find out more information. For example, a web address specified in a small newspaper advert or on the back of a business card.
In such a situation it is crucial that the site is informative. It should be clearly laid out and be content rich.
"Content rich" means that the most important aspect is the information it contains and not the wizzy graphical effect that may have pleased the web designer.
What does your business offer and how can they get in contact with you?