Three students, a iPhone app, 15,000 people inspired to do a small good deed a day.

Subscribers to the free application are prompted daily with a "DoGood"--a simple task from conserving water, to turning out a light, to beautifying the world. When they've accomplished their good deed for the day, they click the application's "done" button.

The program tallies how many users are fulfilling that day's deed, and users can share what they have done on Facebook and Twitter. So far, it's up to 209,214 good deeds.

What a beautifully simple idea! One with a potentially significant overall impact from cumulative small actions from loads of people. A different take on flash mobbing.

How can we leverage this model to implement other worthwhile changes?

And where is the non-iPhone version?

Read the full article here.