MapSurface is a tool that tracks user activity within a web page. Its purpose is to provide an understanding of how users find, navigate and value web pages. It displays this information in a compact widget which sits above the web page. Andy Budd has written an excellent review which is worth reading. http://www.andybudd.com/archives/2006/02/mapsurface/index.php
A browser within your browser.
siteFlow is a cross-browser tool that enables you to browse multiple pages (i.e those featuring next/previous buttons, like Google's search results) and archived web content, faster and with less effort than the usual one-page-at-once browsing. It adds an extra layer of interactivity (literally and figuratively) on top of web pages. Turbocharge your web reading.