If you have reason to be setting up your own web server on a Mac, office-based or home-based, these are very clear instructions from a get-you-started perspective. There are a number of reasons you might want to do this, including ease of mass distributing documents and data to a group.
Please note that many basic consumer internet contracts disallow you running your own web server. And furthermore, for even the most basic web page, I would recommend hosting remotely... I do so with all the web sites I am involved with.