You don't even need to compare answers, per se. I use SO as a way to know what documentation to check. That is, if I want to X, the official documentation is oftentimes extremely difficult to parse through; to do X you have to instantiate a Foo, with an instance of Bar, etc etc etc, and all you have are API level docs. They're usually written the reverse of what I need to solve the problem (given function X -> understand what it does, rather than given what I want to do -> use function X; this gets even worse when you get higher level concepts, where what I want to do -> implies doing 4 different things in this API -> 4 different functions/data types that need to be strung together).

SO and its ilk give me an example that I can start to cross reference with the API level docs, to figure out how to pull it all together, and also where to look to find the "gotchas", tweaks, and options.