Next time someone tells you Twitter is good for nothing, tell them this: thanks to the site, enough money has been raised to build 13 schools for the world’s poorest children.

That’s all thanks to Twestival, a global event held yesterday in 175 cities around the world. Local organizers held parties in venues “hired” without charge, with the aim being to donate all ticket money (plus raffle, auction receipts, and extra donations) to a chosen charity. They then promoted the events primarily through Twitter, though non-users were welcome to attend: a total of 6,740 people took part in the global events.

Last year’s event raised more than a quarter of a million dollars for a water charity, enough to build 55 wells in Uganda, Ethiopia and India. This year’s edition aimed to raise money for Concern, which aims to tackle the root causes of extreme poverty, most notably by helping provide for health and education needs.

At the time I wrote this, the total revenues had hit $310,976.29. There are many ways this could be spent, but the best way to picture that total’s effect is this: it’s enough to build THIRTEEN schools, each with a fully-furnished classroom for 30 children, then train a teacher for each class, build a well to give the pupils clean drinking water, AND give each child a meal during the day for a year.

And that’s pretty good going for 140 characters.