The digital version of The Sun, the countrys most popular tabloid newspaper, attracted more than 100,000 subscribers in the four months since it started charging for online content, publisher News UK said on Friday. Newspaper groups are looking to develop additional revenue streams from online publishing to counter falling print circulations and tough advertising markets, but The Sun is the first mass-audience British tabloid to put all of its online content behind a paywall. Though its early days, we are encouraged by the strong start, David Dinsmore, the papers editor, said. The Sun, owned by media mogul Rupert Murdoch, is following in the steps of his other British titles The Times and Sunday Times.