Thunderbolt provides a simultainious 10Gb/s bandwidth each way that is low latency using PCIe and Displayport technologies. Offering power over port and allowing devices to be daisy chained, this is a feature that desktop PCs have been missing out on for a little while now. Let's hope we see more motherboards adopting this.
We see Thunderbolt in the featured list for the Z77A-GD80.
The Thunderbolt port is a mini DP positioned under the VGA connection.
For more information on Intel's Thunderbolt technology visit: