The idea is for people to use TweetFeel to run search queries for products, celebrities, companies, brands etc. and thus get a notion of what the average Twitter user thinks of them in a matter of seconds.
TweetFeel evaluates real-time tweets about whatever search term the user has entered for positive and negative feelings, presumably taking into account words like ‘good’, ‘sucks’, ‘great’, ‘screw’, ‘love’ and whatnot. Search results flow down the screen as they are calculated as positive or negative, and the service offers an overall percentage number to indicate whether the majority of results are one or the other.
Individually, the results are evidently hit or miss, but in general there could be some interest from marketers to regularly cross-check references on Twitter for the company they work for, the products or services they market and the brands they represent.
Or you can just enter your name and see what people really think about you. In real-time.