Yes! SO is one of my biggest learning resources. I'll go into a little more detail: the minute I want to learn something I start looking on SO for questions to answer. Yep, questions to answer. I can't answer any of them at the beginning, but I sort of try to brainstorm it a little and guess at an answer. And when someone else does answer, I learn a little. Eventually I can start to actually answer a question here and there. Sometimes I get it wrong and people correct me. And that's another learning experience. Repeat on a daily basis or even several times a day and it hugely increases my learning rate on any give tech topic.

What I love about stack overflow is that when you have a technical decision to make you can get a really thorough understanding of all of the pros and cons.

And if people are arguing over which solution is better, its even more valuable, because then you get to learn about all the hidden nuances of each solution and when they matter.