alt Hacker NewsStack overflow (and internet in general) changed the programming as we (at least some of us) knew it.
When I was learning programming I had no internet, no books outside of library, nobody to ask for days.
I remember vividly having spent days trying to figure out how to use the stdlib qsort, and not being able to.
Hmm - I'm not sure I'd say that 'changed programming' - but the internet in general changed 'learning to program'. I can remember when I first discovered gopher and found I could read tons recent material for free, or finding stonybrook on the web - that was like a gold mine of algorithms! :-D