The tiny Roku box is just about as tiny as it can get — so Roku thinks it's time to ditch boxes altogether. This year, the next crop of streamers will plug right into your TV like a USB drive.
The Roku Streaming stick, despite its size, holds and does just about everything a standard box does — sans extra storage, USB jacks, and other things that require a form larger than a thumb. But once plugged in to your TV's HDMI port, it'll present you with the same old Roku menu and streaming selections you're used to from the black puck — all controlled with your standard TV remote. Roku hasn't mentioned whether it'll offer 720p or 1080p resolution yet (nor how much it'll cost), but there will be multiple models eventually — so it's probably safe to expect full HD.
One major caveat: the entire Stick depends on a special type of HDMI port called "MHL," which only a few current TVs have at the moment. The standard could be picked up ubiquitously in the future, but the most important consequence here is that you almost certainly won't be able to use a new Streaming Stick with your existing TV. For those of you looking to buy a new set soon, no problem — for the rest of us, no dice.