Imagine a robot you can control from 1,000 miles away. You feel like you're there. People near the robot treat it like it's actually you in the room -- they include you in conversations. You can speak back, see, maybe point at things, and move around. This is a telepresence robot. There are a bunch on the market.

QB from Anybots (tagline: Your Personal Avatar) looks like a broom standing up on wheels. At the top of the broom handle is a head which contains: a microphone and speaker; a webcam; a screen (that shows a video feed of you); a laser to point at things. On the back of the head is a web address. You visit that website to drive the robot around, and: The robots eyes go dark to indicate to that you are no longer logged in.

AVA from iRobot (tagline: Robots that Make a Difference) has three wheels and is between 3 and 5 feet tall. It has laser and sonar sensors and is semi-autonomous: it can explore a room on its own and build a map. An iPad plugs into the neck and can run different applications. One app might be telepresence. iRobot's first run at telepresence robotics was the ConnectR, (Virtual Visiting Robot) back in 2008. This was a robot vacuum cleaner the shape of a dustbin lid that travelling businessmen would dial into from their hotel rooms to spend quality time with their ignored children. Like this.

The Giraffe video conferencing robot (strap: robots that let you be in two places at once) looks like a mirror on a tall, sturdy, plastic, purple stand with wheels. Uses include remote team management, teletourism and elder care. The Giraffe is not on sale in the USA.

Tilr from RoboDynamics (no tagline) is a flatscreen monitor held aloft a sleek, red, industrial stand. The wheels are concealed under an angular base with black rubber bumpers. A video camera is slung under the monitor. The robot appears to wear a backpack. It is made for factories. It wants to be Iron Man.

From InTouch Health (extending your reach) comes the RP-7, an oversized iron built up to human height, with a TV screen and double video camera on top. "RP" stands for Remote Presence. In the photo, the screen shows a video portrait of the operator - their entire head - which makes it look rather like a laughing doctor is stuck inside the body of the robot. Surely the screen should show just the face of the person?

There's a quote attributed to Albert Einstein: The wireless telegraph is not difficult to understand. The ordinary telegraph is like a very long cat. You pull the tail in New York, and it meows in Los Angeles. The wireless is the same, only without the cat. I'm unable to describe telepresence robots in such terms.