Why does the Thunderbolt Technology port looks just like the Mini DisplayPort connector? Intel and Apple chose the Mini DisplayPort connector as it provided the best of many worlds, from a R&D prospective, and also provided backwards compatibility with existing displays using the Mini DisplayPort connector. Please see Intel and Apple for more information.

Intel's Thunderbolt Site:  http://www.intel.com/content/www/us/en/io/thunderbolt/thunderbolt-technology-developer.html

Apple's Thunderbolt Site: http://www.apple.com/thunderbolt/