Yahoo term Extraction API

PHP: Make Yahoo! Web Service REST Calls - Yahoo! Developer Network
http://developer.yahoo.com/php/howto-reqRestPhp.html

term extraction tag

Better Bayesian Filtering
http://www.paulgraham.com/better.html
A Plan for Spam
http://www.paulgraham.com/spam.html
parsing - Term extraction: Generatings tags out of text - Stack Overflow
http://stackoverflow.com/questions/1100549/term-extraction-generatings-tags-out-of-text