Ever left a nasty note on someone’s windshield because they parked so poorly that they took more than one spot? Or have you ever wanted to alert someone that there car is about to be towed cause they didn’t pay the meter? San Francisco drivers can now alert each other to parking issues through a program called CurbTXT. Drivers sign up by registering their license plates and phone numbers. A sticker on the car gives people an anonymous way to contact the driver through text messaging by referencing the plate number. The service forwards the message to the owner.