It's as simple as that.
Not to get all Sally Struthers on you -- or, rather, Jackie from Roseanne, whose now the spokeswoman for disenfranchised, dirty children -- but the SF Food Bank still needs more money. Even though they distributed food at "a record-breaking pace, handing out groceries to more than 30,000 houses over Thanksgiving," as SF Weekly points out, they are in desperate need of a few bucks. Because of the rapid increase in demand for full bellies, due in part to the Ponzi schemes and the market crash, more people are starving -- sometimes to death.
And now, due to the demand, the food bank will open its pantry to Marin and other Bay Area cities.
So. If you'd like to throw down a single dollar -- just a buck! -- you can donate whatever amount here. Seriously, if you're one of those types who prattle on endlessly via Twitter about street food, or cupcakes, or bacon, or pie (ew, gross), or any kind of food purchased from a dumb damn cart, you should be legally required to donate. Which you can do. Right here.
Update: Er, as SFist commenter whataboutprom pointed out, the minimum online donation is $2. So, yeah, you'll need to throw down an extra dollar.