The facebook like box has been around for some time now but many site owners are not using it. It is a must in advertising in my opinion and let me tell you why. First of all Facebook is the biggest social media site on earth and you can be part of it. Now adding a like box to your site causing a chain effect. First your friends start clicking the like button which shows up in their profile, their friends see this and venture over to see your custom page at facebook dedicated to your site, they click like and all their friends see it and so forth. This drives traffic, increase traffic, alexa ranking, page rank and more.
So my question to you is why don’t you already have one?
You can read more about adding a like box to your site at Dev. Facebook. You can also get widgets for WordPress and modules for Joomla that are already coded out.