Seen this recently? “Text ‘WILDLIFE’ to 20222.”

You probably have, and others like it, as a growing number of nonprofit organizations, such as the National Wildlife Federation, have gravitated to mobile giving as a way to reach people with an easy way to donate.

Ten days after the Haiti earthquake, text-message donations accounted for more than $30-million, or 14 percent of all donations raised.

Yet the strategy can have its drawbacks. While mobile giving can be an inexpensive way to reach the more than 260 million wireless subscribers around the country, questions remain about its effectiveness and reliability as a long-term fund-raising tool.

Indeed, the National Wildlife Federation, which is running a mobile-giving campaign for animals affected by the Gulf oil spill, has recently pulled its text-to-donate message from its Web site.

The reason? The Reston, Va., conservation group wants visitors to donate more — and not think that a $10 text gift is all they needed to give, officials say. The charity aims to track and report on the impact of the oil spill to counter the estimated 186 million gallons of oil that are encroaching on the Gulf’s fragile ecosystem.

Another consideration is sustainability. Once the campaign gets off the news-media’s radar, it’s hard to keep it as a national talking point. The National Wildlife Federation says it has seen a steady drop in text donations when coverage moves to another headline story and after the oil well was capped in mid-July.

“It isn’t on the news” the way it once was, says Anne Senft, the National Wildlife Federation’s vice president of membership and online marketing. “Anderson Cooper isn’t down there anymore.

Organizations should also be aware that cellphone carriers typically receive a percentage of each donation, 2 to 10 percent. Plus, the recipient groups won’t be able to receive that pledged money until two months or so after the initial text, after people have paid their phone bills.

Experts say mobile giving is most effective when different promotional elements are in play. The National Wildlife Federation started the mobile-giving campaign on May 4, two weeks after the oil-spill explosion, with a coordinated media plan that went beyond donations via text.

With the help of the marketing agency Merkle, the group spread the word virally through a variety of social media — placing the text-messaging campaign on YouTube videos, encouraging fans on Facebook to change their status updates, and telling Twitter followers to retweet. Soon celebrities, such as Lindsay Lohan and Alyssa Milano, took on the cause and spread the word through their hundreds of thousands of followers.

The organization also got help from corporate partners. Last week, US Airways embedded the National Wildlife Federation’s mobile text campaign in its in-flight entertainment and tray liners on all of its planes. To keep track of the results, the National Wildlife Federation made a separate keyword: “Text to NWFSAVES to 20222.”

So far, the group has raised $74,000, with its “Text WILDLIFE to 20222” campaign; a separate campaign during a CNN telethon broadcast raked in $70,000, for a total of $144,000—all through $10 donations.

The star-studded two-hour “Larry King Live” telethon—“Disaster in the Gulf: How You Can Help”—on June 21 gave more publicity and more opportunity for two other organizations: United Way and the Nature Conservancy. The televised event, which featured the likes of Justin Bieber, Cameron Diaz, and Jenny McCarthy, raised $1.81-million that evening through a combination of text, Web, and phone donations.

United Way, which urged viewers to text “UNITED” to 50555, raised $45,820, just a fraction of the $500,000 it expects to receive with related donations to the oil spill.

“We don’t see it as a huge fund raiser,” says Sal Fabens, spokeswoman for United Way Worldwide, based in Alexandria, Va. “It’s more of an awareness tool and a way to reach people.”

The Nature Conservancy, the big environmental group in Arlington, Va., raised $69,000 that night via text-to-donate (using “COAST” to 50555) in the two hours of the CNN telethon, says Susan Citro, its director of digital membership.

The Mobile Giving Foundation estimates that the oil-spill text-messaging efforts will garner far less than the $43-million Haiti haul: about $350,000 to $400,000.

Still, about 85 to 90 percent of these donations are from new donors, says Jim Manis, chief executive of the foundation, which helps nonprofit groups enable mobile-giving campaigns by working with phone carriers. “We’re opening up a whole new demographic of mobile giving.”

Indeed, since the Haiti earthquake, the Issaquah, Wash., group says it now has more than 500 charities signed up, with 1,500 mobile-giving campaigns under way.