it is used for sidebars on long pages, so they can be visible all the time user scrolls down the page, instead of a empty space visitors usually see. It is also used for floating top menus, emphasizing it to the user at all time.
It is designed to be flexible, but very easy to use. HC-Sticky applied to a content makes it fixed on the page and always visible no matter how high the page is, or how high the sticky content is. Its packed with many interesting features in case you need them.
HC-Sticky is compatible with all modern web browsers, including IE7, IE8. It requires jQuery 1.7.1or later to work properly (new version of the plugin not tested).