If we’re reading a blog post, looking through a product description or even just scouring through eBay listings..in every case we need to scroll back up to the top of the page if we want to use the site navigation again or perform a site search. Addyosmani is sharing tutorial how to create RocketBar. RocketBar is a simple solution for this which shows you how you can easily provide your users a persistent form of site navigation without them needing to scroll back up.
The way it works is that when a user lands on your page they get to see the default navigation as usual. If they decide to start scrolling however, the top navigation detaches itself from the page and follows you as you scroll down. If you decide to go back to the top of the page (for whatever reason) the navigation goes back to the way it appeared before.