Twitter has enabled Firehose, the complete access to all public tweets without any rate limitation, for more search engines.

This is another Easter egg in Google search. This will take you the official hack page of Google.com

Quick Google is a useful Chrome extension. You can search Google without leaving the current page and see a preview of each result.

Google Homepage Reloaded is a greasemonkey script, which gives users the ability to click Google logo on Google homepage to change the website they search.

List of advanced search operators in Google Wave.

DeskTube brings YouTube to your desktop without any browser. It is a stand-alone desktop application for YouTube

Xmarks SearchTabs improves the Google result page by adding tabs containing the top web sites related to your search.

The Real Live Search is a live search engine created using Bing.com API. It shows search results as you type your query.

Twitter has launched a live updating search widget.

fefoo is the simplest tool to search many search engines at same time.

Twicsy is a search engine for images shared on twitter.

BlindSearch compares results from Google, Yahoo! Search and Bing.

At the very first sight, Topsy would seem to you as another twitter search tool but it is a much more advanced search engine for conversations.

URL bar search is another handy Firefox add-on which makes searching easy with multiple search engines.