Red Cross workers load aid parcels for Haiti earthquake victims
An appeal to help victims of the Haiti earthquake is breaking all records, fuelled by the power of social media.
Type "Haiti" into Twitter, Facebook or Youtube and you soon encounter a message from @redcross sent at 05:38 GMT on Jan 13.
In less than 48 hours, the American Red Cross had received more than $35m in donations - including $8m directly from texts.
"This breaks all world records for a mobile giving campaign," says their spokeswoman, Gloria Huang.
"It's been incredible. People have donated more to Haiti than to Hurricane Katrina or the tsunami in Asia.
"And Twitter has played an extremely significant part."
In the race to fundraise, social network sites have given aid agencies the power to bypass TV and radio and appeal directly to the public.
The Haitian musician Wyclef Jean, for example, has raised $1m for earthquake victims through his Yele Haiti foundation, after appealing for help through Twitter.
We tweeted... celebrities re-tweeted... and after that, the appeal spread like wildfire
American Red Cross
In the immediate aftermath of the earthquake, he tweeted, asking for donations through his foundation.
His 1.3 million followers answered his call - and passed on his appeal with a message: "Spread the word".
Meanwhile on Facebook, hundreds of thousands of people signed up to awareness groups, such as Earthquake Haiti, which offers a link to Oxfam's Haiti relief fund.
On Youtube, the video sharing site, bloggers began posting their own personal appeals, calling for donations.
So, how was this mass mobilisation achieved? After all, the American Red Cross had only a modest number of followers on Twitter when their appeal was launched.
Their trick was to alert popular celebrities - and let their fans on Twitter do the rest.
"Our plan worked exactly like it was supposed to," says Wendy Harman, social media manager, at the American Red Cross.
My worry was - are people just re-tweeting? Or are they actually donating?
American Red Cross
"We have a 'cabinet' of 30 celebrities, who have agreed to ask their Twitter followers to spread the word.
"Within three hours of the earthquake, we had our text number ready.
"We tweeted. The celebrities re-tweeted. And then others quickly followed. People like Michelle Obama, Jane Seymour and Craig Newmark (of Craigslist) got on board. And after that, the appeal spread like wildfire."
Twitter users across the globe began using the RT (re-tweet) function to pass the message on to their friends and followers.
Within hours, the number for the text appeal: "90999" was ranked among Twitter's top 10 "trending topics" - which in turn drove more and more people to donate and spread the word.
Wyclef Jean raised $1m through his Yele Hait Foundation appeal
"We hit that magical viral sweet spot," says Ms Harman.
"Everybody out there seems to know that if you text 90999 you donate $10 to the Haiti appeal.
"My worry was - are people just re-tweeting? Or are they actually donating? It soon became clear that they really were texting and calling."
Using an online map tool, hosted by Mgive.com, she and her colleagues were able to watch as donations flooded in from every US state.
They did not even have to re-send their appeal. The online community were busy spreading the word for them.
"People have been sceptical over the power of the RT (re-tweet) and of Twitter generally," says Ms Harman.
"For example, during the Iran election there was a viral campaign to change your avatar colour to green.
"But this time, people seemed to be saying: 'Let's not do anything cute - let's just donate'.
"I think we have crossed the threshold of novelty with Twitter. People now want to use it to get something good done."
But of course, as with any appeal for charity, people's good will can easily be exploited.
The avalanche of tweets, emails and Facebook groups urging web users to donate carries with it an opportunity for internet fraudsters to profit.
Would-be donors have stumbled on some suspicious websites. On Facebook, a group has been founded with a pledge to donate $1 for every person who joins.
The group has gathered more than 500,000 members. But since it has no administrators, it is not clear who, if anyone, will actually donate the promised money.
Meanwhile, the security firm Symantec alerted web users to an email scam, soliciting donations for Haiti victims, which purports to come from the British Red Cross (BRC).
"The scammers have used the correct postal address, but the BRC does not use Western Union for donations," said Con Mallon, a Symantec spokesman.
"Also, the email address supplied as a contact is not one belonging to the BRC and any money sent using the instructions in this email would end up in the pockets of a cyber criminal."
This "appeal" email was identified as a scam by Symantec security firm
The US Federal Bureau of Investigation issued a warning on Wednesday calling on internet users "to apply a critical eye and do their due diligence" before responding to online requests for aid to Haiti.
"Make contributions directly to known organisations rather than relying on others to make the donation on your behalf to ensure contributions are received and used for intended purposes," the FBI said in its advisory.
Amid the mass of appeals for help sent round on Twitter, even some very expert Tweeters have fallen victim to rumour and misinformation.
Jennifer Preston, social media editor of the New York Times, passed on a tweet to her followers, stating: "American Airlines is taking doctors and nurses to #Haiti for free. Please call 212-697-9767. Spread the word".
However, not long afterwards, she sent her fans a follow up message. "We are now hearing that it might not be true..." she tweeted.
"LESSON LEARNED: do not RT offers to help... unless you confirm."