The card apparently doesn't have a TCP/IP offload engine. Instead, it optimizes UDP traffic, which most games today favor over TCP/IP because of its lower overhead. Bigfoot says the Killer NIC handles tasks like "IP Reassembly, UDP/IP checksum, UDP and IP header verification and stripping," and that it prioritizes both incoming and outgoing packets. Bigfoot claims his functionality translates to impressive performance gains; the Killer NIC can supposedly make 71% more UDP calls per second than an Intel Pro 1000 network card. However, Bigfoot doesn't quote any real-world benchmarks, so right now it's anyone's guess how much the card can actually speed up games.
Raw acceleration aside, the Killer NIC also includes an embedded Linux distribution that can run "FNapps." These FNapps can be "anything from simple packet monitoring utilities [like fire-walls, etc] to full-blown VOIP programs or file-sharing systems: even mini-game servers/chat servers," and they can use the Killer NIC's built-in USB port to store data in USB keychain drives or to interface with USB headsets.
Bigfoot's spiel might make some competitive gamers and enthusiasts salivate, but those users could be in for a nasty surprise when the card hits store shelves. The Killer NIC will launch with a $279.99 price tag, even higher than that of Ageia's PhysX physics accelerator and about the price of a GeForce 7900 GT.