Media owners must find ways to attract and retain talent and create stand-alone digital divisions in order to compete in the era of internet blogs, open access and online communities, Sir Martin Sorrell, the chief executive of WPP, has warned.

The head of the UK advertising group also acknowledged the difficulty of competing against websites that destroyed business models. “How do you deal with socialistic anarchists?” he asked, referring to Craigslist, the popular, free classified advertising site that has been threatening revenues at US city newspapers.