International Business Machines (known better as IBM) is one of the largest computer manufacturers and researchers on earth.
IBM began as the Computing-Tabulating-Recording (C-T-R) company, founded in 1911. They officially became IBM Corp. on February 14th, 1924. C-T-R and IBM have a history of emphasis on research and development to meet rising technological needs.
IBM became important to most people reading this page in 1981, when they began manufacturing and selling Personal Computers with Microsoft's MS-DOS installed for easy use. Though not the first PC, that claim being held by Apple, IBM helped grow the market considerably and became a more major player later on. As Microsoft became more aware of its potential business, it started working with other hardware manufacturers, and eventually its reliance on IBM was phased out. The phrase "IBM-compatible" became prevalent in the Windows era when Microsoft pitted manufacturers against each other, driving down hardware prices and increasing Microsoft's piece of the pie.
More recently IBM is known better for supercomputer research. The company has active R&D in quantum computing, has made breakthroughs in cheap supercomputing with the Blue Gene, and frequently humiliates mankind by pitting our best chess players against computers. In 1997 chess grandmaster Garry Kasparov, world chess champion, was defeated by Deep Blue. Kasparov has since continued to fight the good fight against IBM's chess machines, with limited success.
IBM is currently contracted to supply the processing power behind the Nintendo Wii (powered by a PowerPC processor, the architecture previously used in Apple computers), Xbox 360 (with a triple-core PowerPC CPU), and PlayStation 3 (using the Cell processor).