RED BAND: Members of Reddit's atheist forums have managed to raise over $232,000 for Doctors Without Borders.

Atheist bloggers have shown their charitable side by swarming to donate money to Doctors Without Borders, in what turned into the humanitarian agency's biggest online fundraiser.

Doctors without Borders, also known as Medecins Sans Frontieres, gets about 4000 hits on its US website on an average Sunday. Last Sunday that number ballooned to 50,000 as a horde of redditors, subscribers to the website reddit.com, thundered across the DWB homepage.

Thousands more clicked through from the atheism sub-reddit, a site normally given over to finding holes in religions and picking fights with creationists, and headed for a dedicated site at firstgiving.com, where they have so far given US$180,000 (NZ$232,000).

"It's amazing, what's going on. The amount being raised is amazing, definitely," said Natalie Favre, an MSF spokeswoman in Geneva. "We don't control any of this."

Many donations were tagged with messages such as "Because god won't," "Good without god" or even "Good without Zeus."

"I WAS gonna buy some Taco Bell... but screw it," wrote DJW3NCH, who donated US$5 via firstgiving.com.

Reddit's atheist page, reddit.com/r/atheism, boasts more than 300,000 subscribers while the Christianity page has 20,000.

One atheist reached across the divide to ask what the Christians thought about the donation campaign. A redditor calling himself Duke_Newcombe replied: "What do I think? Praise God. And thank you, r/atheism."

Reddit is owned by Conde Nast, better known as the publisher of Wired, Vogue and GQ. Unlike Twitter or Facebook, it thrives on anonymity, fostering a creative chaos which is divided up into "subreddits" and largely self-policing thanks to guidelines known as "reddiquette" and the desire to collect "karma," the points earned and lost from upvotes and downvotes.

A similar reddit drive raised about US$50,000 last year. This year, donations picked up as many redditors promised a few cents for every upvote they got, and then sought to outdo each other by upping the cash value or matching what others gave.

Jennifer Tierney, who is in charge of fundraising at DWB, said the money from reddit was not earmarked for any particular project and could be used for any of DWB's work, which this year included fighting cholera in Haiti and the Democratic Republic of Congo and responding to emergencies in Libya and Ivory Coast.

A big priority will be to fill the gap left by the Global Fund to Fight AIDS, Tuberculosis and Malaria, which is cutting grants because of economic problems faced by donor countries.

DWB normally gets a few million dollars a year from about 250-300 third party fundraising events, anything from reddit to a child selling home-made lemonade on the street corner. Reddit has contributed about 10 percent of that total in a few days.

"Things are looking good. Our donors have been really, really loyal to us, which is wonderful. I know it's tough for people out there and it's great that they're continuing to support us," said Tierney. "This is very good example of how the communities online can get together and make a huge difference."

Although it welcomes the windfall from reddit, DWB is aware of the dangers of expecting the reddit atheists to donate every year, and it is not planning to chase them for money.

"We're not doing a heavy push on fundraising. We're really not trying to overwhelm people that way," said Tierney. "I think the most important thing on social media is you engage people and they get to know you. It's a great space for that, and try not to use it to force a donation. It doesn't work that way."