We often think of sociability as a single axis, from introverted to extroverted. On one end sits the shy geek who prefers to interact with the world via a computer screen, and on the other strides the back-slapping frat guy, calling everyone "bro" and speaking loudly enough to be heard on the other side of the city.
Yet I think it's more useful to think of sociability as a classic 2x2 matrix. Not only is their an Introverted/Extroverted axis, there's also a Socially Skilled/Socially Awkward axis. The result is a more insightful way to categorize the people you meet.
This is the classic image we have of the shy introvert, terrified of saying the wrong thing. Thank goodness Al Gore invented the Internet! By focusing on written communication, you can still build a rich set of relationships.
Yet introversion has nothing to do with shyness or awkwardness; rather, it simply indicates that interacting face-to-face with others consumes energy. It's entirely possible to be both introverted and socially skilled. My wife Alisha hates talking with other people, and has to psych herself up before going to parties that include mostly strangers, but knows how to put people at ease and draw them out. If you fit into this category, you should recognize that you have social skills, but using them is likely to tire you out.
This is a bit of a sad case; think of someone you know who is gregarious, loud, yet fundamentally clueless. This doesn't have to be a frat-boy a-hole; many times, this is simply someone who loves spending time with others, but has difficulties reading social cues. You might find yourself in this category if you love going out, yet find that people always make excuses and leave their conversations with you. If this describes you, your best bet here is to pick up a copy of "How To Win Friends and Influence People."
This is the classic image we have of an extrovert. Note, however, that this doesn't mean loud or overbearing; in fact, this kind of person excels at being inclusive. These are the social geniuses who can and do relate to anyone. Fortunately, most of them have good hearts, or they'd rule us all.