"Better Search through People" applied to image search? Or Yahoo! Visual Answers?
BoingBoing references a "bug identification service" called "What's that bug?" that allows folks to send in photos of bugs for identification. (Looks like Yahoo featured this three years ago too...
Based on a cursory glance at the site, this isn't exactly what I'd imagined. Folks don't actually upload photos directly but rather email them to the curators who do the identification. I was envisioning a site where folks actually upload content directly, and the community (presumably of entomologists) identify the critters.
There's a group on Flickr called "Guess what this is!". This is more of a guessing game. Then there's "What flower is this?" I've also seen geographic scavenger hunts on Flickr, i.e. the "Guess where ______" meme... There's also "Name that _____", featuring "Name that music video" and "Name that movie".
This theme, i.e. getting folks to help me name that plant | part | flower | etc. definitely scratches an itch. This is all coolness!