I can’t really say much about Tuyuan yet since it’s in Chinese and there isn’t much information (translated page here), but it certainly looks like they’re trying to tackle the facial recognition problem that has destroyed many a startup.

We’ve seen Riya (now focused on ecommerce via Like.com), Ookles (never launched), and Polar Rose (in private beta for nearly a year), among others. Most recently Tagcow came on the scene, but it turns out it uses humans to tag photos, which tends to produce bad data.

Will Tuyuan be any different? We have no idea yet. But we’re contacting them to find out. More soon. Thanks for the tip, Orli.

New service TagCow caused a bit of a stir over the weekend. The product seemingly solves the problem of auto-categorization and tagging of photos, something that seems to still be beyond the processing power and software skills of most startups.

Users upload photos – thousands of them if they like – and within a few minutes the photos are returned with stunningly accurate descriptive keywords that facilitate searching and browsing later on. The product worked so well, and the site had so little description of the technology behind it, that I speculated that humans were doing the work in the background.

And….I was right. A reader sent in a tip that they saw the service on Amazon’s Mechanical Turk service, which is a web service that gets people to do things that are fairly hard for computers to do. TagCow is actually a perfect fit for Mechanical Turk.

Users are paid 4 cents to properly tag a group of five photos. I tagged a few photos with “TechCrunch” twenty times each, collected my 4 cents, and moved on. My guess is it would take about two minutes to properly tag the five photos. That means if you work steady and without breaks, you can make $1.20/hour. More if you are speedier.

Most people have thousands of digital photos sitting on their hard drive. And the vast majority of those photos aren’t tagged or searchable. Want to find the 300 pictures of your youngest son amongst 10,000 others? It’s not going to happen. Unless you’ve been diligently tagging and categorizing those photos over the years, and who does that?

The problem is obvious. The solution, not so much. A trail of failed startups have tried to tackle the problem with a fairly serious application of technology, including: Riya (now focused on ecommerce via Like.com), Ookles (never launched), and Polar Rose (in private beta for nearly a year), among others.

And now suddenly TagCow appears, which allows users to upload photos and have them tagged within a few minutes. The technology appears to be “magic,” meaning there’s no explanation of it.

If there’s a mountain in the photo, it’s tagged. A dog? yep. A yellow cup? Absolutely. It does people, too. Upload an image of a person and say who it is, and all other images you upload will be tagged with that person, too. The service also integrates with Flickr and will auto tag the photos you have on the service.

Thomas Hawk, the CEO of photo site Zooomr, tried the service and declared it “really, really cool,” although he wonders how it works.

The answer is, humans do it. I note that the TagCow site is careful not to say anything about the tagging process, and never use the word “automated” or anything else that would suggests computers are doing the work. Munjal Shah, the founder of Riya/Like, agreed, noting that it recognized a witch in Thomas’ photo – he says this just isn’t something a computer can do today.

I haven’t confirmed this yet. I’ve emailed the company for a description of how the service works but have yet to hear back. Until we do, I’m betting that humans are the taggers. Note that Google has effectively thrown in the towel and uses humans for this kind of work, too.

TagCow appears to be offering the service for free, so the cost side of the business may be a problem for them down the road. And the business is definitely a little sketchy. Worried about the privacy of your data? Just don’t click on their Privacy Policy or Terms of Use: “Privacy policy is TBD.” and “Legal stuff TBD.” Not exactly a way to build confidence.