The types are realted to the version. you have USB 1.0 and USB 2.0, the second allows higher data rate transfer. There is no difference in the connector, so you need to get the device features to know which of them are supported.
there are two kinds of usb namely 1.0 and 2.0.
the difference in features lies in the speeds of their data transfer
no you can not diffrentiate by looking at them
Planet Analog seem t be running some features news on USB... maybe you can have a read over there... pretty informative.... I thnk there will be eventually 4 parts to this articles
The latest USB is the USB-OTG (On The Go)
This version is different from the others in that it has the potential of playing the role of a master. Till this, only the PC was the master communicator with all other USB devies acting as inactive slaves.