Two Points On Understanding Stack Exchange Culture
Stack Exchange sites tend to have two reputations. The first reputation is that they're the best place to go when you're stuck with something, because if the answer's not there already then you know you'll get a good once quickly. The other reputation is for being unfriendly (even tending towards hostile) with respect to newcomers; there's a question on Quora about it and Stack Exchange themselves even did some research into the friendliness of comments on their sites (read The Hunting of Snark by developer hero Joel Spolsky). This is my attempt to help explain why SE sites can give an impression of being unfriendly despite being filled with some amazing people.
What Makes It Seem Unfriendly?
Generally (as the research SE performed) comments etc. are neutral in their voice and more are friendly than not, so it's not really a case of what's being said: it's what's being done. Oftentimes a newcomer's question will quickly be closed, or their answer deleted, and unless a useful comment is left (moderators are warned if a post is closed/deleted without comment) they might be left wondering why. In essence it comes down to rules.
The power of the sites comes from the fact that they're concise; the model strives for minimum discussion and maximum accuracy. Duplicate questions offer no benefit: they in fact make it harder to maintain a resource as technical changes could occur over time and it's easier to maintain one question/answer on the topic than tens or hundreds. Answers that say "I'm having this problem too" offer no help, questions that are vague and open-ended simply invite long winded discussion which is great at times, but not in an environment that's purposefully designed to not cater for it.
Stack Exchange sites are built around rules in order to maintain a good level of quality, these rules are enforced by the community which means they're often enforced very quickly, and I think is where the feeling of unfriendliness arises. If you're new to the network chances are you'll treat it like any other forum, but it's very different and that's why it's easy to come unstuck if you don't understand the framework.
Two Rules For Getting The Most Out Of Stack Exchange
It's very easy to start asking and answering questions on Stack Exchange, the interface looks nice and simple (which it is) and that encourages people to start without looking at some of the excellent introductory help content. The problem with that is that they miss out on a few nuggets of vital information in there.
1. Avoid Discussion
This site is all about getting answers. It's not a discussion forum. There's no chit-chat.
So that's the first thing—it may seem impolite to some degree, but there's no need for comments like "thanks, this worked for me too", just vote up the answer/question instead and keep discussion down to a minimum so that the real information is easier to find. While writing this post I've dealt with two automatic "low quality" flags from the system, both of which were answers along the lines of "I'm having this problem too". This is exactly the kind of forum-style content that Stack Exchange sites attempt to avoid, so that those people looking for answers find real answers.
2. Research, Then Explain Your Question
Focus on questions about an actual problem you have faced. Include details about what you have tried and exactly what you are trying to do.
People don't want to spend their time answering a question when it's obvious that the asker has not done any research at all. If you've looked online (including searching the site), and read the documentation then ask a question if you're still stuck. You may also notice that the site suggests similar questions that may have been asked, so be sure to check those out. If your question is deemed to be a duplicate of an existing one it will be closed for the reasons I described earlier. When you do decide posting a question is required, make sure it contains enough information to get an answer, guesswork doesn't help anyone and again, results in discussion which future readers may have to dig through to find the gold.
Edit, Flag, Edit and Edit
Once you've been around the site for a while and earned a decent level of reputation you'll gain ~new superpowers~ the ability to edit questions and answers, regardless of who they were written by. Don't let this power go to waste! Everyone is responsible for the content of the site and making sure it's up to date, if you discover something that's not as it should be then edit and fix it, it's a key part of maintaining a useful resource.
Flagging is another powerful tool offered available to everyone with even a little cred to their name, and doing so allows you to raise attention to posts that might need some moderation attention and/or removal, but moderators are the last line, the "exception handlers" as Pat Patterson put it in our Dreamforce presentation. Four close flags from any four members will close a post without a moderator even knowing about it; the site's community is it's best asset and one that I'm proud to say is growing quickly and doing an amazing job, so please join in!