The Mormons – the Church of Jesus Christ of Latter-day Saints – believe they're more likely to get converts thanks to social media than knocking on doors.
Despite 200 years of pounding the pavements looking for converts, the Church says its experience is now put to best use on the web.
Elder Erich Kopischke, told The Times that "one post on Facebook could reach 900,000 people in an instant". He argued it would take many months, if not years, to knock on that many doors.
The head of the Church's European operation is in London to mark the 175th anniversary of American missionaries sailing for Liverpool on July 1, 1837.
Mormonism has been increasingly in the news thanks to Mitt Romney's bid to oust Barack Obama as President of the United States. A spoof musical, The Book of Mormon, is due to open in London in March.
Nearly 500,000 have already liked the Church's official Facebook page, and there are 900 Mormon missionaries in Britain. There are nearly 200,000 members in Britain, as well as two temples. The Church also owns 15,000 acres of UK land.
Kopischke said "If you think about the idea of door-knocking, Jesus once said, 'Your mouth speaks what your heart is full of'. Why do people knock on doors? Because their heart is full. Why do people use social networks? Because they have something to say. Door-knocking is sometimes understood as aggressive proselytising.
"If I want to share with you what is really on my heart or that I have observed something, [social networking] is easier than to make the trip."