Hundreds entered.

Twenty one made the first cut.

In the end, only three were left standing.

They now take their rightful place as the sexiest, most eligible non-profits alive.

I write, of course, about the winners of Netsquared.org’s Mash-up Challenge: a competition for the best use of web tools for social good.

The 21 finalists — some of which are mere concepts, some of which are established websites looking to expand and scale — ranged from:

A proposal to use your mobile phone to do impromptu volunteer activities…to a system for getting targeted alerts about pending genocide legislation… to a  site that allows everyday citizens to submit questions for journalists to pose to lawmakers…

(full list of finalists)

Over the course of the two-day Netsquared Conference at the Cisco Center in San Jose, CA, the 21 finalist projects presented, jockeyed, politicked, and schmoozed their way toward the final voting session, during which conference attendees voted on their favorites. I myself was on the receiving end of an outrageous bribe — a bic pen — by a non-profit that shall remain nameless.

Check out my video blog on the winners:

Here’s my other coverage of the event, starting with my favorite post:

Live-blogging from Netsquared: Second Life and the Non-profit Commons (the most meta panel I’ve ever attended)

More videos and posts after the jump…

Live-blogging from Netsquared: Knowmore.org (which gives ratings for corporations and organizations based on their social responsibility)

Live-blogging from Netsquared: Freecycle.org (a Cyber-curbside. Give things away instead of throwing them away)

Live-blogging from Netsquared: StepitUp2007.org (nationwide, grass-roots movement in the fight against global warming)

Liveblogging at the Netsquared: Squarepeg (which leverages personal preferences to help users organize around social causes)

Live-blogging from Netsquared: Mobile Voter’s ‘Volunteer Now!’ (which gives users mobile alerts on volunteer projects they can partake in at that very moment)

Live-blogging from Netsquared: MetaVid.org (which makes video clips of lawmaker hearings universally accessible and mash-up-able)

Live-blogging from Netsquared: Healthycity.org (which allows users to get detailed demographic info about their neighborhood)

Live-blogging from Netsquared: AskYourLawmaker.org (which allows users to submit questions for journalists to pose to lawmakers)

Live-blogging from Netsquared: SocialActions.com (which allows uers to search for social action campaigns across 29+ websites)

Live-blogging from Netsquared: iLovemountains.org (a Web 2.0-tricked out resource center and action center against mountaintop removal coal mining)

Live-blogging from Netsquared: iLoveMountains.org (Part 2)

Live-blogging from Netsquared: Social Signals on Community-Building (tips on how to grown your online community)