count is not useful in determining whether a user's tweets get retweeted or whether the other users engage with them. Pal et al. designed features to measure a user's authority on a certain topic. For example, retweet impact refers to how many times a certain user has been retweeted on a certain topic. The impact is dampened by a factor measuring how many times the user had been retweeted by a unique author to avoid the cases when a user has fans who retweet regardless of the content. They first used a clustering approach to find the target cluster which has the highest average score across all features, and used a ranking algorithm to find the most authoritative users within the cluster. With these authority detection methods, social Q&A could be more effective in providing accurate answers to askers. References External links People associated with social information seeking include: Eugene Agichtein Rich Gazan Jung Sun Oh Sanghee Oh Jeffrey Pomerantz Chirag Shah Social information processing