Windows 7's Virtual Wi-Fi sounds complicated—it virtualizes your wireless adapater into as many wireless adapters as you want—but making your machine think it has more than one wireless adapter is pretty useful:
It'll let you tap multiple hotspots at once, or probably more useful, make it easier to set up a mesh network, where every system in the network acts as a repeater—one "adapter" grabs a signal, another passes it on. In Windows 7, you're limited to one virtual adapter, but that's all you need to share a Wi-Fi connection with other computers.
You can't do it yet because the drivers for wireless adapters to make this happen don't exist yet, but they will, so you'll see it by the final release for sure. Pretty useful, though I wish they'd make Network and Sharing a little easier still to navigate around. Maybe that's too much to ask. [I Started Something via Engadget]