U.S. cell phone users have contributed about $4 million to the Red Cross in $10 increments, by far the largest outpouring of support via mobile devices in history.

Wednesday was the "largest mobile donation event that we have ever seen," said Jenifer Snyder, executive director of mGive Foundation, the nonprofit group that is working with the Red Cross and wireless carriers to channel the donations.

To donate to the Red Cross, mobile users are texting the word "Haiti" to the number 90999. Snyder said the money is coming in at a rate of roughly $200,000 an hour.

"We could be handling more," she said. "We are not at capacity."

As of 10 a.m. Thursday, mGive has collected about $3.7 million, all of which will go to the Red Cross. By noon, Verizon Wireless said donations have surpassed $4 million.

On Thursday morning's "The Early Show" on CBS, Secretary of State Hillary Rodham Clinton asked Americans to contribute to the Red Cross via text donations. And on social networks Twitter and Facebook, users continued to message one another to text money as well.

Other charities, such as singer Wyclef Jean's Yele were also collecting mobile donations. To send $5, donors can text "Yele" to the number 501501.

Verizon Wireless said its users have pledged more than $1 million to the Red Cross through text donations. The outpouring easily surpassed records for mobile giving.

In the aftermath of Hurricane Katrina in 2005, the Red Cross collected $400,000 from mobile users. A year earlier, following the Asian tsunami that left 230,000 people dead, the organization received $200,000 through text messages, Verizon Wireless said, citing industrywide figures.

Jeffrey Nelson, a spokesman for Verizon Wireless, called mobile donations a "new stream of philanthropy."

"So many folks who are texting $10 now might not have been at a place to write a check, or call a toll-free number or send mail," he said.