If you built your site in 5.5.x, scrapbooks are a from an earlier version and you have no need to read on.
In concrete5 version 5.3.0, we introduced centralized content repositories called scrapbooks.
With 5.5, we decided to take what we'd learned from the scrapbook, rebuild it completely and solve all the problems we hadn't anticipated when 5.3.0 came out. We split personal scrapbooks into the Clipboard, which is just a simple way to copy existing Blocks and paste them around a site. We moved global scrapbooks into Stacks.
If you upgraded your site from 126.96.36.199 you will still have access to your scrapbooks. We urge you to use Stacks instead. A more indepth explaination of why can be found in this how-to:
Scrapbooks were a great stepping stone; they filled a very real need, and let us experiment with how to bring the functionality to our users. But Stacks improve on scrapbooks in every way, and we're glad they've arrived.