Many projects in computational biology lead to the creation of a small application program or collection of scripts that can be of use to other scientists. A natural progression is to make this tool available via a Web site or by creating a service for it, from now on collectively called "Web resource."

We conducted a survey among providers and users of scientific Web resources, as well as a study on availability. The following rules reflect the experiences and opinions of over 250 scientists who have answered our questions and who use Web resources regularly, as well as our own experience. The study of availability allows us to draw objective conclusions about the characteristics of those Web resources that are still available and correlate the features that distinguish them from disappeared or nonfunctional ones. These ten simple rules aid you in designing and maintaining a scientific Web resource that is available to anyone interested in using it.