Most influential tweeters of all? Depends on the topic

If you really want to know the most influential people tweeting on the hot topics of the day, go to pulseofthetweeters.com. The website went online in May and has been tracking the top trending topics from Twitter in real time ever since.

The website was created in the laboratory of Alok Choudhary, John G. Searle Professor and chair of electrical engineering and computer science at the McCormick School of Engineering and Applied Science. It grew out of the thesis project of Ph.D. candidate Ramanathan Narayanan.

"The question we're really asking is: whose opinions are most interesting and influential on any given topic?" Narayanan said.

The website uses a specialized algorithm to rank the most influential people tweeting on trending topics. For example, if you are interested in baseball playoffs, the website will rank the most influential Twitter users who actively tweet about baseball playoffs and also have a following of baseball fans who tweet about the sport.

"There are about 50 million tweets produced every day, but most of us only read 10 or 20 tweets in one sitting," Narayanan said. "So, which tweets should you read? Which tweets are being read by media experts on any given subject, such as politics, law, fashion, food? We provide that information for users."

The algorithm for the website combines dynamic data mining, sentiment analysis and network analysis in real time. Besides identifying the most influential tweeters, the algorithm can tell you whether their tweets are positive, negative or neutral. It also offers related topics to explore.

"Discovering patterns, opinions and sentiments from massive number of tweets is challenging in itself, but discovering influencers and leaders for specific topics is a major technological advance in data mining," said Choudhary, also a professor at Northwestern's Kellogg School of Management.

While celebrities gain huge followings in the Twitterverse, the top influencers on the hot topics of the day are likely to be people with much lower profiles.

"If someone from BP is tweeting about the oil spill, for example, his opinions are likely to carry much more weight and be of much greater interest than those of Ashton Kutcher, who has a legion of followers," Narayanan said.

The technology can filter out spam, too. It is able to identify bots that send bogus tweets and rank them at the bottom of search results.

"The good thing about our system is it's completely automatic, and it needs minimal human supervision," Narayanan said. "We are able to generate really useful choices for people who are interested in Twitter."

In the future, the website could track many more topics, including those that are not trending on Twitter.

"The website could be used by companies who want to know what people are saying about their product," Narayanan said. "They could find out if top influencers are saying positive, negative or neutral things about their product, and that may have a lot of implications."