Like many of its competitors, including Tweetmeme, which is set to launch some interesting new features itself later today, dailyRT aggregates retweets and displays them in a real-time feed on its homepage. DailyRT's advanced search features, however, make this new service stand out from the crowd. You can, for example, filter results based on how many followers a user has. Or, thanks to dailyRT's oAuth integration, you can tell the service to only show you results from users you already follow. In addition, you can also restrict searches to specific dates.
DailyRT also allows you to save your searches, which is especially useful if you regularly search for the same terms.
One problem we noticed, though, was that dailyRT does not support the Boolean searches (AND, OR, etc.) that Twitter's own search engine offers. This takes at least some of the usefulness out of the service's advanced search features. (Update: DailyRT's Chris Williams tells us that Boolean searches are coming tonight).
We'd love to see a service that, in addition to dailyRT's advanced search features, would also add some of the personalization that a custom memetracker like MicroPlaza offers. But, for now, we'll have to do with dailyRT's advance search which is already a great step forward.