Here's another little gem that few know about or take the time to utilize. Guest books on a site, like a mailing list, gives the site owner information about the visitors and, like feedback forms and surveys, offers insight from the visitors. But the signing of a guest-book is where they become a gem.
You will be amazed at how many visitors you'll receive by this simple process. It's like leaving your business card for a curious passer-by to pick up.