I like a9.com. Its a search engine thats run by Amazon. It uses Google’s search engine for web based searches so the results are of good quality. It also lets you search a plethora of other sources (some 200 and counting)
The trick is that the results from different sources appear in multiple panes in your browser, all at the same time. This helps by showing you different perspectives of your search term and a broader scope of what your search means to different sites. Therefore you can write better searches and find what you want quicker with little effort.
Initially I thought it was just another gimmicky engine trying to catch the search engine train until I realised the usefulness of the multi-engine search. I got started with it because a9 users get a small discount on Amazon purchases just by signing in and using the search engine (the discount kicks in after a couple of weeks of use)
There is a toolbar for both Firefox and Internet Explorer which does the sign in automatically so you’ll be eligible for that discount in no-time. The other aspect is that the system has a diary, bookmarks and history features that are computer independent which means that you can have a very fast & portable online lifestyle. Today I realised that a9 had been tracing my browsing history for the past 6 months. Many would feel this is a risk of their privacy, but more so I found it useful. Any firefox browser on any platform can install the a9 toolbar. Those using a desktop search tool to keep tabs on their browsing history are no longer restricted to a single platform.