This was all before 2001 while I was in high school, with books being very hard to get in Serbia, so internet was my go to resource.
Now to be honest, even after SO, I only use it as a last resort. Somehow only 1/20th of the problems I hit match what people seem to hit on SO :/
Perhaps this is an age difference thing? I'm 29 - I learned to program between 2003 and 2010 from online resources, mostly in the pre-SO era. I learned BASIC, Perl, PHP, and Python entirely online. My impulse was always to just Google things, although I fully admit finding results was more time consuming and frustrating back then. The only language I learned from a book was FORTH, and that's mainly because it's an older language and Starting Forth is one of the few good resources on the language even today.
I picked up a book last month to learn Clojure...how does SO help to learn a language start to finish? I don't even typically refer to SO for syntax questions, I'm sure it has that information but it doesn't seem like a very convenient place to index it. But maybe that's my subset of languages...
I probably end up on stack overflow a few times a week, and it is helpful...but I'd be fine without it if Google would just return better results.
And I really did find myself buying a lot more programming books than I do now. When's the last time you picked up a book just to learn how to use a language - just the ins and outs of the syntax? I used to do that all the time, and then I immediately stopped when SO became popular because I could just google for what I wanted and SO would always tell me.