Your algorithm seems like it's well made, though I have not taken a close look at it's capacities yet. My suggestion: get a better interface. You're competing with similar websites such as http://www.newspond.com
The ui is really nothing special, but that is by design. We want it to work with JavaScript off and to be easily crawled so that Googlebot understands the structure. Spiders and crawlers have yet to catch up with the times and still have difficulty finding their way through sites that use JavaScript for navigation.
"À la carte" feeds. I'm building this into the site as we speak. There will be a sign up form to create an account and to get a subscriber id. Subscribers can define filters. Within a filter is a list of keywords and a schedule (monthly, weekly, daily, hourly, or real-time) to generate a feed that matches your keywords. The "API" then would be HTTP GET and the response is RSS. Simple.
