When you enter a search term, sucks/rocks searches the web for several positive and negative phrases using that term. The score is the fraction of positive results to the sum of positive and negative results, normalized to 10.

Whoosh is a fast, featureful full-text indexing and searching library implemented in pure Python.

A small, free plugin for Safari that adds keyword search to the browser’s address bar.

For MIT's Project SIMILE, David Huynh built an amazing series of web tools for exploring and organizing structured information. Two months into his new gig at Metaweb, he's done it again. On this edition of Interviews with Innovators, host Jon Udell asks Huynh about his Parallax prototype, which creates a powerful new way for users to click their way through related sets of information in Freebase. In essence, a Wikipedia-like database built on a semantic web foundation.

YubNub is a command-line for the web. After setting it up on your browser, you simply type "gim porsche 911" to do a Google Image Search for pictures of Porsche 911 sports cars. Type "random 49" to return random numbers between 1 and 49, courtesy of random.org. And best of all, you can make a new command by giving YubNub an appropriate URL.

ack is a tool like grep, aimed at programmers with large trees of heterogeneous source code.

With MonitorThis you can subscribe to 22 different search engine feeds at the same time. Enter a search term and click the 'make monitor.opml' button to get a list of rss feeds in OPML format.

Sitemap is an XML file that lists URLs for a site along with additional metadata about each URL

Developer oriented search engine

shows relationships between two search terms