Daniel Sundheim built a reputation as a savvy stockpicker at Viking Global Investors, a hedge fund where he helped oversee $32bn in assets. That helped him raise more than $4bn in seed money when he launched his own fund in July.

Yet while Sundheim, 41, is now a big name in the hedge fund world, he might not have broken in without an obscure website called Value Investors Club. Writing anonymously on the site in 2002, Sundheim posted a 3,700-word takedown of a dental company, Orthodontic Centers of America, assailing its business model and financial results. The post caught the attention of a few hedge funds that shorted the stock, profiting as the shares slid. (The company filed for bankruptcy protection in 2006 and emerged under the name OrthoSynetics in 2007.)