Joining a new community can be a daunting task for a myriad of reasons. The angst can be especially strong when joining a new technical community, some of which have a reputation for being acrimonious and tough on new members.
While it's possible to stumble into a den of iniquity, I think you'll find most technical communities to be fairly reasonable, and following a few simple steps can ease your transition from non-member to member.
A good fit
The process begins well before you actually join a community. The first step is to ensure the community is a good fit for you, and you are a good fit for the community.
This sounds simple, but every community has a distinct culture, attitude, philosophy, and accepted norms. If you're new to a topic, a community aimed at industry professionals is not an ideal place to start. Similarly, if you are a grizzled expert looking for an answer to an in-depth, extremely complicated problem, a community for beginners is almost certainly not a good fit. Either way, the impedance mismatch will almost certainly lead to frustration on both sides. Similarly, some communities are going to be very business oriented and formal, while others will be extremely lax and laid back. Many are in the middle. Picking a community that suits your personality, or minimally isn't an anathema to you, will help ensure you enjoy participating long term—which leads me to the first step.
Browsing around and participating in the community in a read-only mode initially is a good idea. This doesn't mean you shouldn't immediately create an account or join, just that you need to get a feel for a place (be it virtual or physical) by browsing around a bit. Lurking for a little while will help you acclimate to the community's rules and culture, and you can ascertain whether you think it's a good fit for you.
Depending on the venue, the details of what introducing yourself will mean can vary widely. Once again, be sure to do this in a way that is consistent with what is acceptable to the community you're joining.
Some places may have a dedicated outlet for introductions, while in some communities it may imply filling out your profile with meaningful and relevant information. If the community is a mailing list or IRC channel, a brief introduction included with your initial query may make more sense. This will give the community an idea of who you are, why you'd like to be a part of the community, and will also let them know a little about yourself and your level of technical proficiency.
While what is acceptable will vary largely from community to community, you should always be is respectful. Avoid flame wars and personal attacks, and always try to be constructive. Remember, once you post something on the Internet, it's there forever, and for everyone to see.
Remember that well-crafted questions receive better answers quicker, as I pointed out in my October column, The Queue.
Once you know a topic well, forgetting that at some point you didn't know the basics either is all too easy. The "be respectful" mantra applies here just as much when answering a question as it does when asking. A lengthy technically correct answer given in a condescending manner isn't the way you want to introduce yourself to a new community.
Even in a technical community, not all discussion is a question or an answer. In those cases, remember that differing opinions and challenging others' point of view is healthy when done in a respectful and thoughtful way, and without insult or personal attack.
The most important thing about participating in a community long term is to remember to enjoy your time there. Participating in a vibrant community is a great opportunity to learn, grow, challenge yourself, and improve. It's not always easy, but it is worth it.