Lots of PCs lack adequate overcurrent protection...

I've seen one form where there's common overcurrent protection for several ports, so all ports go dead once protection kicks in.

Worst case is weak protection that works more like a fuse, permanently killing the port (but saving the PC)

The ideal is of course per-port resettable overcurrent protection, which notifies the OS on overcurrent condition.

I have a powered USB hub myself that gives about 700mA to my N900. However, everything else connected to it dims...