A Guidebar is a navigation tool to your site. A collection of links and information to let the visitor to your web site find their way through it easily.
Guidebars come in a number of varieties. The most common is the Primary Guidebar, often seen on the left side of the web page. This is usually on all your pages, and gets the visiting user from where they are to the content they want.
Wilmoth Web Design provides an advanced programming Primary Guidebar that can expand to give more detailed choices upon entering a more general area. This helps keep your Guidebar uncluttered so the visitor can find their way more easily. Also it can provide 'tooltips' on most browsers. When the user hovers over a link, they can get more information about it before actually having to click it.
There are additional Guidebars that you can add to a site, such as quick links at the top of the page, or convenience links at the bottom of each page, so that the user doesn't have to scroll back up after reaching the bottom inorder to access another area, or links to areas not in your main guidebar.
There are also regional Guidebars, ones that usually more limited to a small group of pages, or a single page, to help the visitor jump between a selection of related content that isn't significant enough to warrent cluttering the Primary Guidebar.