Kickass! When you paste the Disclaimer text into the box, it suggests "the darjeeling limited" and "potty training". The first three paragraphs of Yegge gave me "faithfulness" and "registry cleaner". Just make it work, and it will be awesome.
It's simple and accurate.
The main problem is not the algorithm but the input data. Our system learns from millions of tagged blog posts among other sources. The quality of the tags varies a lot, and most of the work we do is about deciding what data to use for training.
Please contact us if you'd like to use the API, if you need to do up to 5k queries per day or so it shouldn't have much of an impact on our server.