Bus monitor Karen Klein didn't ask the world for sympathy, and she definitely didn't request money. But once Internet users watched the heartbreaking viral video of young students harassing Klein, they reached for their wallets.

This is viral philanthropy, through which users of online communities, such as Reddit, Facebook, Twitter and other platforms, spread awareness and raise money for those who need it.

Last month, Redditor Max Sidorov saw the video of Klein. The students' hurtful treatment reminded him of his own experiences with bullying. He decided to spread the word and directed people to the crowdfunding site Indiegogo to raise money for Klein's much-deserved vacation. Meeting the $5,000 goal within five hours (and reaching over $680,000 with 11 days left in the campaign), the "Let's Give Karen - The bus monitor - H Klein A Vacation!" campaign shows the power of leveraging online communities for great causes.

"With a connected web, we all have a chance to be Batmen/women of sorts," Alexis Ohanian, founder of Reddit, told Mashable.

Ohanian is no stranger to crowdfunding. He used Crowdtilt to raise $15,000 in about 36 hours to send an anti-SOPA message to Lamar Smith.

See also: How Anonymous Reddit Donors Charmed Mainstream Media

In addition to the Klein campaign, Reddit users have raised $100,000 to protect the Faraja Children's Home in Kenya, more than $212,000 for medical non-profit Doctors Without Borders and $50,000 for treatment of a three-year-old's rare blood disease. There's even a special subreddit called Random Acts of Pizza, where you can donate a pizza pie to those in need.

“I think we've moved from a world of transactions to a world of relationships.”

However, Reddit admins aren't the only ones fostering philanthropic movements. Anyone can launch a fundraising effort over the web. Individuals and organizations have raised large sums of money for numerous causes and through various communities. According to an Indiegogo spokesperson, influential communities that direct people to the crowdfunding site include YouTube, Facebook and Twitter, in addition to blogs like Gawker and Gizmodo.

Once a worthwhile cause garners attention, philanthropy seems to be the natural next step.

"Social media and crowdfunding can change the way that people connect with the causes or the passions they believe in," explained Slava Rubin, founder and CEO of Indiegogo. "I think we've moved from a world of transactions to a world of relationships."

Rubin founded Indiegogo in 2008 as a crowdfunding platform for the independent film industry, but within a year, it extended to include any cause. From that point on, people could use Indiegogo to raise money for just about anything.

See also: 9 Essential Steps for a Killer Kickstarter Campaign

Indiegogo is one of numerous crowdfunding platforms, including Kickstarter, Kiva, ArtistShare and more — though some platforms are tailored to specific kinds of projects. Kickstarter, for example, clearly states in its community guidelines that users may not raise funds for causes or charities. Broader platforms like Indiegogo, then, are better suited for such philanthropy.

Many project leaders turn to crowdfunding after they see other campaigns reach success. Colleen Wainwright wanted to do something meaningful for her 50th birthday, and set out to raise $50,000 for WriteGirl, an award-winning Los Angeles-based non-profit that empowers teenage girls through writing. Wainwright had been interested in crowdfunding since since she saw a friend use Kickstarter for his webseries.

"I love Kickstarter, and it had a somewhat higher profile in my own new media circles, but since this was about raising money for a bunch of girls who needed every dollar, I figured the prudent way to go was with a site that let them keep as many of those dollars as possible," Wainwright said. "Indiegogo would have taken a bigger cut had we not raised it all, but at least it wasn't an all-or-nothing proposition."

The 50 for 50 for WriteGirl! campaign did indeed raise it all, and then some — more than $61,000 — by Wainwright's birthday on September 13, in addition to a $50,000 matching grant from an anonymous foundation. But how do you promote a cause well enough to raise so much money?

"I did a very little bit of pump-priming with my own mailing list of about 3,000 people," Wainwright explains. "I think I made two announcements in total, up front — one on my blog, and one in a monthly newsletter — telling people that I was plotting a super-secret project to celebrate my upcoming 50th birthday, and if they wanted to know what it was before anyone else, to opt-in to a new list. Then I created a whole new, separate list."

Almost everyone said he would promote it, meaning the campaign enjoyed a really strong start — around $10,000 in the first day or so. Wainwright thinks this is critical because it fuels excitement and "makes people feel like they're part of something that has a chance."

Rubin seems to agree, and has the statistics to back it up. "As soon as you get [the] ball rolling, which is typically about 30-40% of your funding, you can get social proof, so then strangers will be willing to fund more easily," Rubin says. "Believe it or not, though, your number-one tool to start off with is email. That's where you have to pull in your inner circle first, and then you can go out through these other channels."

"You don't harangue, harass, wheedle and provoke. You create epic shit that people want to be part of."

Several of Wainwright's friends immediately pledged to donate to the 50 for 50 campaign when it went live, but she specifically made sure not to ask for money overtly.

"In addition to being horrible at asking for either help or money, I had a little pride tied up in the whole thing: I wanted to see if the project was interesting and meaningful for people to donate to, or pass along word of without me doing a lot of arm-twisting," she said. "You don't harangue, harass, wheedle and provoke. You create epic shit that people want to be part of. If my shit wasn't epic, so be it."

Wainwright also made announcements on Twitter and Facebook, but the 50 for 50 campaign also found success through YouTube.

"I introduced videos because interest in the other media — my blog posts and interviews [with women writers] — didn't seem to be moving the needle," Wainwright explained. She admits she didn't keep track of hits and how they correlated with donations, but people liked the videos, and engagement went back up. "I tried to mix it up, to throw curves in there and keep them fresh. And I am not above making an absolute fool of myself to keep people entertained," she said.

Rubin says that the Indiegogo team has learned what really drives the tens of thousands of campaigns on the platform toward their targets — and videos are number one. Campaigns with videos will raise 114% more money than those without. Additionally, users who update campaign pages every five days or less raise significantly more money than if they update every 20 days or more. Lastly, if a campaign has four or more people on its team, it will raise 70% more money than a crew of one.

While it may seem easy to promote a call to action online, crowdfunding takes hard work and dedication in order to generate action.

"Occasionally, there's a lottery ticket occurrence," says Wainwright, referring to Karen Klein's crowdfunding explosion, "but most of the successful ones I've seen have been people who are leveraging platforms they've built painstakingly, over a long period of time, and/or offering something epic and intriguing. It floors me that anyone would think all they need to do is build it and people will come, like there's some magic Internet lever you pull so money comes out."

It's clear that online philanthropy is booming for both project leaders and donors, already complementing traditional forms of fundraising and perhaps soon to replace them. Whether it's raising money on a platform like Indiegogo or even instilling change through petitions on Change.org, philanthropists are using web virality to alert the world to worthy causes.

Sidorov recently updated the Klein campaign's page: "To tell you the truth, you guys have inspired me to do more. I have some plans in the works to start other big projects to bring positive change to as many people as I can. I'll keep you guys in the loop. There are so many people around the world that need [our] help!"

And that seems to be the goal: Help those in need, even when they don't necessarily ask for it.

Images courtesy of iStockphoto, ideabug, twing, fotosipsak.