The key difference though is that you got timely help from a forum by asking a question. However, as the next person trying to find the answer to the same question, I would have to wade through multiple forums with pages of answers (the answer you got was on page 3 of 5) with people asking clarification and the tangent from someone else (on page 2) about drivers I care nothing about.

Stack Overflow was designed so that the next person with the same question could find the answer more easily. The next person could avoid having to go through Sun's Java forums, and CodeRanch, and /r/Java, and /r/JavaHelp and the comments of someone's blog post, and ... Too many places with too much tangental knowledge that wasn't well indexed. Despite the idiots and trolls having posts removed,

With Stack Overflow, one knows that if they ask a question there (admittedly, that fits within the focus and quality guidelines) they will get an answer - not someone commenting on another comment that is indistinguishable from an answer (comments vs answers). And if they search Stack Overflow, and find the question that has an answer - it is an answer. That is the key value proposition of Stack Overflow in that the next person who has the same question as you do can find it easily.