Internet users today are inundated with information. We get masses of email; we’re interrupted by instant messages; and we must remember to check social networking sites, news sources, and company Web sites daily—or even many times each day. Web searches produce more hits than we can sift through, as we try to find what we’re really looking for.

Managing this much information is a very complex task. “Syndication” technology—such as RSS and Atom—and feed readers might provide some support, but issues related to the analysis, classification, evolution, retrieval, and other information are open problems. Information overload, therefore, represents a big challenge for software applications seeking to help users by collecting, grouping, classifying, indexing, selecting, searching, ranking, and filtering pieces of information.

This special issue seeks original articles examining the state of the art, open problems, research results, tool evaluation, and future research directions in overcoming information overload. Appropriate topics include

- building and managing information repositories;
- extracting, matching, classifying, clustering, measuring similarity, analyzing natural language, and indexing applied to information;
- retrieving, aggregating, and visualizing information;
- personalizing, ranking, collaborative filtering, and keyword-based search engines; and
- syndication technology and feed readers.