Microsoft acquiring GitHub, the largest open-source code repository, brings them full circle to the infamous 1976 open letter by Gates to computer hobbyists who were sharing, not buying, their BASIC software for the Altair. The irony should be savored.

In ’75, Microsoft got its start when Gates and Allen adapted BASIC for the Altair 8800. BASIC was originally written by two Dartmouth professors, who put it in the public domain. As Paul Ceruzzi wrote in A History of Modern Computing:

“with its skillful combination of features taken from Dartmouth and from the Digital Equipment Corporation, [BASIC] was the key to Gates’ and Allen’s success in establishing a personal computer software industry.”In 1981, MS-DOS, Microsoft’s operating system for the IBM PC, was acquired for $75,000 from the tiny Seattle Computer Products (who themselves borrowed it from Digital Research’s CP/M).

That wasn’t the last of Microsoft’s creative pursuits.

Microsoft Word was originally written by Xerox PARC engineers as Bravo (but never marketed); it became a Microsoft product when Microsoft hired one of its original authors, Charles Simonyi, away from PARC.

Excel was derived from Visicalc by Software Arts, and from Lotus.

And the graphical user environment that is Windows first appeared at PARC in the Alto personal computer, and then in the Apple Macintosh, before becoming Microsoft’s flagship product.

The world is powered by building on and recombining what has come before. Too often, where we stand on this fundamental creative process depends on whether we profits from creating or defending our innovations.