"Eurekster allows you to build a custom search portal, or “swicki,” around any topic of your choice. Rather than returning millions of results like a generic search engine, swickis learn from the search behavior of a community of enthusiasts and experts, making it easy for you to quickly find what you’re looking for within a particular topic. In addition, you can easily share a swicki with others and add a swicki buzzcloud to your site or profile (“grab” a swicki), which will dynamically display the hottest searches and give you quick access to that swicki and its community."
Need to include a search engine on a website you're creating that will search only the specific sites you want it to? Gigablast's Custom Topic Search is customizable and will support up to 500 websites.
"We find and share the best tools to get whatever you want done. Simply. iTools helps you use the power of the Internet by giving you a clean interface to make use of many of the best tools of the Web."
"Using search engines to locate relevant content typically means hunting through pages of results. Rather than searching for quality web sites, StumbleUpon members are taken directly to web sites matching their personal interests and preferences."