Today very popular Web portal sites, social networking sites, online media sites, commerce sites, etc., provide platforms for millions of visitors to visit daily and express their opinions on a wide variety of subjects. The site operators strive to increase the number of visitors, and the visitors often make use of several means at their disposal to participate in the formation of collective opinions. In this article, we examine the various means becoming available to the Web site visitors to express their opinions, and the challenges that both the site operators and the general public face to ensure the visitors’ opinions are fairly and accurately reflected in the collective opinions.