If you're a big user of Twitter search (formerly Summize), you'll probably like Monitter three times better. That's because it lets you search for not just one word or phrase in the Twitterverse, but three at one time.
Leaving it open in a tab or window turns your browser into something like a stock ticker, with new Tweets fading in as long as they've got the word or phrase you've typed in. Each previous search is also kept as an RSS feed right below.
In addition to its simple one-page presentation, blog owners can drop it into their site with three custom keywords of their choice. You're also able to paste in multiple instances in case you want to create a giant array of keywords that continue to be tracked.
According to creator Alex Holt's Twitter feed, location awareness is coming to the next version, which means users will be able to filter tweets based on where they're searching from, something you can do with Twitter's search engine by tweaking the advanced settings. Holt says part of the inspiration for Monitter came from Adobe AIR based Tweetdeck which was one of the first tools to focus on side-by-side Twitter organization. Also mentioned is PopUrls, which was one of the inspirations for Guy Kawasaki's ever expanding AllTop feed aggregator.