1. A method of measuring changes in interest of a community of users, the method having a scalable time complexity of O(N x ) where 0<=X<=1.0 for a universe of text on the world wide web comprising: obtaining user fingerprints of users that constitute the community at a first time, the user fingerprints comprising vectors whose components are scalar cumulative weights associated with topic categories; combining the vectors that comprise the user fingerprints to obtain a first community user fingerprint; obtaining user fingerprints of users that constitute the community at a second time, the user fingerprints comprising vectors whose components are scalar cumulative weights associated with topic categories; combining the vectors that comprise the user fingerprints obtained at the second time to obtain a second community user fingerprint; and calculating a mathematical difference between the first community user fingerprint and the second community user fingerprint, the method configured to measure the changes in interest of the community of users and have the scalable time complexity for the universe of text whether the universe of text includes text written in one language or in more than one language.