The Mini DisplayPort is a video output interface found on new Apple laptops. So far, Apple is the only company to support it on shipping products, but they're hoping to change that by licensing it for free to companies that want to support it. (Hat tip to Ars Technica.)
is an emerging video standard promoted by the Video Electronics Standards Association (VESA). Developed to replace Digital Visual Interface and eventually to replace the ubiquitous analog VGA interface found on personal computers, DisplayPort offers greater bandwidth, enabling users to run a 30-inch screen, for example.
With the refreshed MacBook, MacBook Air and MacBook Pro models, Apple jumped to the bleeding edge of DisplayPort support, introducing the 24-inch LED Cinema Display, which only began shipping last week. The Mini DisplayPort Connector fully supports the VESA DisplayPort protocol, but uses a fraction of the space—hence its introduction with refreshed Apple laptops.
Apple is offering a license to "develop or distribute plugs, receptacles or other devices implementing the Mini DisplayPort Connector" to interested parties; a Web page on the Apple Developer Connection describes the connector and offers links to the evaluation license and other useful information.