Ushahidi is wonderful: I've argued for years we need to crowdsource information in emergencies http://tinyurl.com/2ab638 Great to see they're actually doing it!
-- W. David Stephenson

BTW: I'm writing a book, "Democratizing Data," http://tinyurl.com/bn9wsl, on how free access to structured data, such as the Citywide Data Warehouse feeds in DC that powered their Apps for Democracy contest, can result in a range of benefits, including crowdsourcing. Please contact me if you have tangible examples.
-- W. David Stephenson

Please add http://jobspooler.com to the list as a US based general job and task crowdsourcing platform.

Please add http://www.createmytattoo.com to the list. It is a US based site for croudsourcing custom tattoo designs.

Shouldn't http://www.LawnMowingOnline.com be on this list? They provide inexpensive lawn mowing services throughout the US using crowdsourcing.

Hi - I'm afraid LawnMowingOnline doesn't really qualify as a crowdsourcing company.

Why do you think LawnMowingOnline.com isn't crowdsourcing? The meet the definition on wikipedia: "outsourcing tasks, traditionally performed by an employee or contractor to a large group of people or community (a crowd), through an open call." LawnMowingOnline outsources lawn mowing to a large crowd through an open call.

However I do see sites on here that are not crowdsourcing like I-StockPhoto because there is no open call, they just have a online marketplace for selling photos, similar to Amazon allowing private sellers to sell goods or eBay stores or Craigslist.

Fixed broken URL on JobSpooler, added CreateMyTattoo and LawnMowingOnline