In the old days, you couldn't combat global hunger just by buying an imaginary vegetable. Back then, if you wanted to make a trivial but virtuous gesture of pop-culture consumerism you had to make a trip to Tower Records and purchase a copy of "Do They Know It's Christmas?" or "We Are the World." Casual philanthropy required at least some effort. Today, it's a different story, writes Greg Beato. Log in to FarmVille, shell out $5 for some cartoon corn seeds that you can plant in your virtual field, and a genuine 3D family in Haiti may get a chicken, goat, or micro-loan from one of several nonprofit organizations that are partnering with FarmVille developer Zynga.