Acronym for International Business Machines.
Known as Mama Blue or Big Blue, this is a company that makes BigIron and software. They pride themselves on having the most patents of any company in the world(?). They were the dominators of the computing industry when "computer" meant "mainframe" or even "mini computer". When they decided to step into it, their mere presence in the PersonalComputer market decimated the competition. Young upstart Microsoft managed to play with dirtier tricks than even IBM though, and ever since, they've lost their #1 position in the IT industry. They tried to gain their own back with OS/2, but that attempt didn't succeed as far as its potential should have allowed it to. IBM have now sold their PC arm to cut their losses.
In recent years they have moved heavily into services, which now generate over half their revenue. They've found Linux an excellent platform to build onto and are now realigning a lot of their business around it, dedicating huge sums of money to its promotion. Even so, it does not seem like they are trying to dominate the community; their current attitude is quite agreeable and they appear to be able to peacefully coexist with the idealists while making all the money they want.
Currently being sued by SCO over alleged breach of contract (for the officially licensed AT&T-derived Unix code) in relation to Linux.
72 pages link to IBM: