Twitter is also a leading silicon valley tech company with hundreds of extremely intelligent employees. You could easily argue that they may have one of the best engineering staffs in the world. Given that, of course they would use open source versus buying enterprise products.
In terms of engineering staff, they are the exception, not the norm. A company like home depot or kelly moore paints would have a tough time relying on open source for all their operational software.
In terms of engineering staff, they are the exception, not the norm. A company like home depot or kelly moore paints would have a tough time relying on open source for all their operational software.