I'm exploring how to improve the relevance of Yahoo Term Extraction API results. My initial question to Yahoo revealed that their system uses a semantic network to relate words and phrases. I'm experimenting with a two-step process: first, extract terms without a query to identify the most relevant term, and second, use that term as a query in a second extraction to refine the results. This might improve relevance, though it doubles the number of API calls. I plan to test this in my DeliTag and AjaxTag applications.
I'm developing an AJAX application to automatically generate Technorati, Feedster, and MSN search boxes with relevant tags for my blog posts. It's a JavaScript webservice queryer that uses results from one service as input for another. Currently, it only supports IE6/7 due to cross-domain data source import restrictions in Firefox. I'm exploring JavaScript code signing as a potential solution. The application integrates with Yahoo webservices, with plans to include Technorati and hopefully Feedster. There are security concerns regarding my Yahoo key. I aim to have a prototype available for feedback soon.