The Public Library of Science (PLoS) ONE is a peer-reviewed, open-access and online publication that publishes articles from all the branches of science and medicine. Their progressive decision not to limit papers based on subject matter "facilitates the discovery of the connections between papers whether within or between disciplines" and allows for a richer site. Visitors will find that one of the unique features of the site is the ability to rate the quality of the articles published. Any registered user can rate the articles, and anybody can become a registered user. The "For Readers" tab near the top of the homepage has a link to "Guidelines for Rating", which provides visitors with the three rating categories, and their scales, one to five. The categories are "Insight", "Reliability" and "Style", and comments are also allowed to accompany the article. Visitors should not miss the link to "Collections", under the "Browse Articles" tab. Some of the collections include "The Paleontology Collection", "Prokaryotic Genome Collection", and "Biodiversity of Saba Bank".