The Roomba is a
autonomous vacuum cleaner, the first true
consumer robotic product. There have been other robots designed for consumer use, but before the Roomba was created, a household robot was a hobbyist
toy that people used to impress their gadget-minded friends. There are also very many successful commercial, military, and industrial robots, but you won’t find them in someone’s
living room.
The Roomba is a product of the iRobot (nice Asimov reference) Company, whose tagline is “Robots for the real world”. In addition to the Roomba, the company also makes robots for explosive ordinance disposal and hazardous materials handling and telepresence for commercial, government, and municipality use. The Roomba is currently their only consumer product.
Basically, the Roomba is programmed to take a route through a room that covers the entire floor with minimal overlap, vacuuming as it goes. In addition to replacement batteries, filters, and such, accessories include a self-charging base, where the robot can direct itself to recharge when it recognizes its battery is low, and a “virtual wall”, a device that beams a signal that tells the Roomba a boundary exists. (One must still empty the dirt bin oneself.)
Interestingly enough, Robert Heinlein wrote about the first consumer robot in the book The Door into Summer, where he basically foretold that the first household robot would be no more than an autonomous vacuum cleaner. His protagonist’s “Hired Girl” brand of robotic vacuum cleaners paved the way for robots in every facet of society. iRobot should read that book (or at least the technology bits, there are many prophetic gadgets described in it beyond household robots) as he also describes some improvements like a feature where the robot vac picks up unknown stuff from the floor and puts it on a tray for later sorting by the owner.
The Roomba has been pretty successful in the marketplace, with several companies making lesser, knock-off products (imitation is the sincerest form of flattery.)
A military robot iRobot makes is also referred to as a "doomba".