OnePipe allows you to create custom RSS feeds of sites based on a keyword or phrase through a simple bookmarklet. There are several sites that allow you to create filtered feeds, but this tool allows you to create them from within your browser and without any type of login or registration. Combined with text message alerts, you can create a system that alerts you when a particular web site posts about a specific topic or term. The post linked above outlines several possible scenarios for using this tool.

By way of Lifehacker...

Technorati Tags: onepipe