LinkExtend

Wikipedia said:

LinkExtend is an extension for Firefox and Flock web browsers. It conveniently offers information on various issues of great importance. It's the first meta-site-safety tool, bringing users a safer browsing experience. It gets its safety ratings from eight different services.

In addition, it offers meta-ratings for child safety, ethics and site traffic. It provides pagerank, page age, pages visited, and many other useful site tools. It enables the user to get information about a site before visiting it, such as, files, titles, reviews and more.

All the information LinkExtend offers is immediately available on the toolbar for the site that is currently being browsed. All the features are also shown next to the search results for Google, Yahoo and Ixquick. Additionally, LinkExtend can be used through the context menu on any link in any site.

I have just started using this and so far it seems worth having. I will be removing WOT and possibly Norton Toolbar (comes with NIS).

Any feature can be disabled or hidden and the items on the toolbar can be moved to another toolbar.

http://www.linkextend.com/

I don't notice any significant slowdown on a 1Mb line.