From the webpage:
uClassify is a free web service where you can easily create your own text classifiers. You can also directly use classifiers that have already been shared by the community.
Examples:
- Language detection
- Web page categorization
- Written text gender and age recognition
- Mood
- Spam filter
- Sentiment
- Automatic e-mail support
- See below for some examples
So what do you want to classify on? Only your imagination is the limit!
As of 1 July 2011, thirty-seven public classifiers are waiting on you and your imagination.
The emphasis is on tagging documents.
How useful is tagging documents when a search results in > 100 documents? Would your answer be the same or different if the search results were < 20 documents? What if the search results were > 500 documents?
I first saw this at textifter blog in the post A Classifier for the Masses.