At the risk of seeming "less mysterious," I'll explain what I do with Twitter Search, Yahoo! Pipes, and Pingie. Twitter's track feature (which used to send users SMS messages based on certain keywords the user provided) has been broken for a long time, and it doesn't show any signs of recovering soon. So using that combination of tools, I can search for a specific term or terms, grab the RSS feed, run it through pipes if I need to concatenate feeds or create conditional filters, and then send the resulting RSS feed to Pingie, which sends me an SMS message whenever that search terms appears in a tweet. If you're just looking for specific words (like your username for replies and mentions), you can skip the Pipes and go straight from the search RSS feed to Pingie. Want IM alerts instead of SMS? Use IMfeeds instead of Pingie. Slow and imperfect but better than no track at all. ;) - Rick Turoczy from FriendFeed MT Plugin