The editor of one of the world's most successful news websites has raised the prospect of Stephen Fry's Twitter page being regulated.
Martin Clarke, editor of the Daily Mail online, told the Leveson Inquiry into press standards that additional regulation may be a "dagger to the heart" of British online media.
Mr Clarke was talking about the difficulty of regulating web news publishers and bloggers with large audiences.
He said: "You can't slice and dice the internet up into different bits... Stephen Fry has four million followers on Twitter. He can reach more people in one hour than I can, so is he going to be regulated?"
The editor said a situation could not be allowed to exist where people could discuss matters on Twitter and Facebook but newspapers were not able to report them.
He said: "It would be very unpalatable for the newspapers or websites like the MailOnline to be placed under a heavier burden of regulation when the rest of the internet is not placed under any burden of regulation."
Mr Clarke also hit out at an uneven playing field for British media - hamstrung by being bound by European courts and different rules for foreign competitors who are all part of the English language global news market.
The editor cited two examples. He said French celebrities were able to sue British media for photographs taken of them in America which did not breach UK laws or regulations. He said the MailOnline was fighting one such legal bid.
Mr Clarke said: "It seems unreasonable for foreign nationals to try to export their own country's levels of privacy wherever they travel around the world."
He added: "We don't find the current regulatory environment too disabling. There are occasions when it can be frustrating or irritating but that is not something that happens as a dagger to the heart of our business. But if things were significantly tightened then it may well do."