Microsoft on the other hand do everything in house
The Windows XP disk defragmenter tool is made by Executive Software, and I'm pretty sure that there are plenty of other components that have been "bought in" and integrated with Windows, which the general public then perceive as being a Microsoft product.
Makes me laugh when I hear people say "The windows defrag tool is rubbish, I prefer to use Diskeeper"... it's the same product! Diskeeper is still going strong though, and ins't an example of "Microsoft assimilation".