You may be able to use it for a home server but unless you have a particular need for the NVIDIA parallel processor you're better off with other cheaper systems. If you're looking for a tiny home server check out a Raspberry Pi or ODroid: http://hardkernel.com/main/products/prdt_info.php
You can get the same performance for less money with a normal graphics card. Assuming you need a workstation card (for support or something), http://www.newegg.com/Product/Product.aspx?Item=N82E16814133... the Quadro K600 also has 192 cores and similar ~330 GFLOPS performance. It will probably use more power, but it's about the same price. If you use gaming cards instead of workstation cards, it gets much cheaper.
I've been looking for something to replace my Ouya as an XBMC box, but with enough power to support the incoming 4K content. I'm not sure this does it.
You'd probably be better off waiting for a 4K codec to settle out, and for hardware decoding support in new chipsets. As it stands, HDMI is barely capable of pushing 4K to the handful of displays that will accept it.
