Paul Myers, a biologist at the University of Minnesota, Morris, puts his top rank down to “tapping into the broader areas of liberal politics and atheism” and a rich vein of “resentment against the reactionary religious nature of American culture”. Scientists can easily translate their expertise into blog posts, adds Myers. “Sometimes, I just summarize some basic concepts as I would in the classroom.” But you are certain to fail if you write as if for a peer-reviewed journal. “It doesn't work on the web,” says Myers. “A blog's more like the conversation you'd have at the bar after a scientific meeting.”



Being a group blog is key, says contributor Jack Krebs, president of Kansas Citizens for Science. “We have some of the most well-informed observers and critics of the 'intelligent design' and creationist movements.” The nature of the topic helps too, he adds. “There is an interest, a hunger even, for thoughtful analysis of the issues related to evolution and creationism.”



Stefan Rahmstorf, a climate scientist who blogs at RealClimate, puts its success down to the hot topic and expert contributors. It helps to have “a passion for explaining things as clearly as possible, and a hell of a lot of patience to deal with all those comments rolling in”. Gavin Schmidt, at NASA's Goddard Institute for Space Studies in New York, says the blog fills “a hunger for raw but accessible information” that goes deeper than newspaper articles, but is more easily understood than the scientific literature. “Magazines fill a void, but they can't react or interact as effectively as blogs.”



Frequent posting of original content is crucial to building an audience, says Sean Carroll at Cosmic Variance, which is produced by five physicists. But taking “stances that are provocative and make people think” also helps. One needs to become the place to go for a subject, he says. Citing other blogs is a sure-fire way to get their notice and maybe a citation in return, he adds. But he cautions that citation counts and rankings can be a distraction. “It would be a shame if people worried about traffic and not about having a good blog.”



Nick Anthis, who only began blogging in January, knows the reason for his site's swift rise to fame. During a political censorship row at NASA in February, Anthis was the first to reveal that a key official had lied about graduating from Texas A&M University. “Before I knew it, it had exploded into a major national news story and he resigned.” After an initial spike in traffic, many stayed on as regular readers. (See how the blogs were ranked)

Click here for a full list of the Top 50