News Corp yesterday joined the ranks of media groups acquiring much smaller internet companies, with a $580m cash purchase of a company which owns, in Rupert Murdoch's words, "some of the web's hottest properties".

The acquisition is one of a handful that Mr Murdoch, who runs News Corp, is believed to be looking at as he tries to map out a strategy to capture a share of the strong growth in internet advertising and to retain newspaper and television audiences.