There's a principle in the psychological theory/techniques known as Neuro Linguistic Programming (NLP) – you cannot NOT communicate. That's worth remembering in your career (and indeed, your whole life).
Humans are social animals and are communicating constantly. In your career, of course, communication is important, which is why I wanted to do a separate essay on this.
First, there are the obvious ways we communicate – inflection, word choice, etc. Those are things we may mess up simply as we take them for granted. We get used to a way of speaking, we have friends used to our odd expressions or bon mots – but how do we come off on the job search? What are you saying on the job search, and are you saying it right?
Secondly, there's ways we communicate we don't think of – how we dress, do our hair, the cars we drive, etc. Even if it's not "communication" of the deliberate-information-transmission type, everything we do says something about us to someone – it just depends what a person is looking for.
It's important in our careers, since they are expressions of us and our goals, to think of how we communicate, and go beyond our words and gestures. Positions, inflections, how we dress make an impact – so can the fact if we have business cards, dressed appropriate to our message, etc.
Being geeks of course, we're information based, and we know our subculture. This can be good or bad, we may use inappropriate slang, or be able to communicate with our fellows. Also being information-based, we can come up with some dynamite ways to communicate.
Always remember, you're always communicating. So take control of it.
– Steven Savage