Related link: http:www.yubnub.org
I love yubnub.org! Here are three commands I created today to make my job easier:
obsd — list matching OpenBSD man pages
nbsd — list matching NetBSD man pages
amarank — display Amazon.com Sales Rank for the given ASIN/ISBN
Go to yubnub.org and try them.
Example: obsd device
Example: nbsd device
Example: amarank 0596000278
What’s your favorite yubnub.org command?


Re:
How is this better than the keyword search feature offered natively by browsers?
Eg. http://kb.mozillazine.org/Using_keyword_searches
In combination with the SmartSearch Firefox extension, you can use keywords both manually from the address bar as well as by highlight a search term in a webpage.
http://www.pitt.edu/~crp11/firefox/smartsearch/
This is a killer feature.