I've been a big fan of firefox quick searches for quite some time - this allows you to type in things like wp in your browser url bar and it will perform a wikipedia search for you.
There's lots of them - I downloaded a heap a while ago into my browser that allowed me to search various language API documentation, cpan, mysql doco, google, wikipedia, IMDB etc.).
However it's a bit of a pain, deploying these bookmarks to all of the machines that I use - and I'm pretty sure delicious bookmarks does not support quick searches, and I was struggling to find the original list of bookmarks out on the interweb.
Enter yubnub, it's a "social search bookmarking-like" thing - simply install the search engine into your firefox browser and start using the yubnub "community" quick searches.
Some of the interesting quick searches it provides include: g - google search gn - google news search wp - wikipedia search flk - flickr search gim - google image search deli - delicious tag search cpan - search cpan jd - search javadoc.org mysql - search mysql documentation
A list of core yubnub commands is here: http://yubnub.org/documentation/jeremys_picks#CoreCommands It's actually a lot more complex than that, but I'll let you guys explore it a bit more - let me know what you think!