Please change the "correct answer," as it is clearly wrong.
I made a huge mistake purchasing the Thunderbolt Display. It's beautiful and works great with a Thunderbolt-equipped Mac, but that's it. There's zero compatibility, even backwards with DisplayPort, a technology that uses the same video protocol and connector form factor... even with MacBooks released after the fact! It's unfortunate, because the potential was so great for this display... but producing a high end monitor today that doesn't support any common video standards even via adaptor? Absurd and outrageous.
For a while (2005-2010), Apple was moving towards MORE compatibility and utility and I was one of their biggest evangelists, but it's like they decided that philosophy was for the birds and what people really want is expensive silicon that contains as little function as possible. Jobs gets such a bad rap regarding this, but under his direction Apple's devices were more connectable than ever and open standards flourished in the Apple ecosystem. Since his departure, our devices might as well be in a glass box.
Thunderbolt is awesome. I love it. But there's absolutely zero excuse for omitting a theoretically compatible technology from a so-called "professional" monitor. It's just assumed (rightfully) that a modern display will support more than one device.
/rant
Looking forward hopefully, with the release of USB Type-C, we will see Thunderbolt as a standard output in GPUs and I can start to get some use out of this display, again. I'm still a Mac guy, but I've been building PCs for gaming, server functionality, and other workhorse applications for over 10 years. This ordeal has certainly taught me to do extra research before buying any Apple product, as normally standard functionalities can no longer be assumed and their absence is often revealed after the fact with little fanfare.