I've been following and instilling the 10% rule for years for people starting out, especially when it comes to barefoot running, but I've always stated that this shouldn't be treated as a hard-and-fast rule. Looks like research is on the way to confirm that this doesn't really make much difference toward preventing injury. I think it should still be followed when starting barefoot running: not for injury prevention, but to acclimatise your feet to the new sensations.