Instead of reaching out to companies for large donations, social media enables NGOs to reach bigger audiences and raise more donations. Recently, I came across an interesting project that has been leveraging the benefits of social media to raise awareness about several causes and gathering donations through microfunding.
Microfunding allows users to donate very small amounts ($10 for example), while working together towards larger goals. Although the donated amounts are bitty, the few donated dollars by each user sum up to make a difference in the lives of many others. The 12for12k Challenge has been able to reach a very large audience through Facebook, Twitter, blogging and other social media tools.
You might not give a lot with microfunding, but when you add up all of the people giving, you can reach significant fundraising goals to support your cause.