USB 3.0's highest speed (termed "SuperSpeed" to easily separate it from the previous, equally clearly labelled, speed grades "LowSpeed", "FullSpeed" and "HighSpeed") requires more pins than USB 2.0 speeds, so the connectors are different.

Here's a link, picture of USB 3.0 micro plug on the right: http://en.wikipedia.org/wiki/USB#Cable_plugs_.28USB_3.0.29.

You're getting some confusing answer. The simple answer is NO: the USB3 "superspeed" signal is carried on different pins. USB low/full/high speeds carry data in both directions on a single pair of differential wires. SuperSpeed has a separate pair for each direction, and it doesn't share anything with the existing D+/D- lines.

Basically, a "USB 3" connector has two completely distinct signaling environments. It's basically two cables in a single bundle. This is in fact literally true for hubs: a "USB 3 hub" is actually implemented as two distinct electronic devices: one working on the old lines and one on the new.

That said, there is an extension on the Micro B port that allows the extra SuperSpeed pins to be connected in such a way that the port remains compatible with old connectors. I've never seen one in the wild.

Yes, it's this one: http://en.wikipedia.org/wiki/File:Connector_USB_3_IMGP6033_w...

The socket is compatible to normal Micro USB plugs while the plug is not.