First, the social dynamics are much as he describes, although I would certainly not argue as he does that pretense is "eliminated". It is somewhat attenuated. The attending population can be segmented in lots of ways, but here's mine:
|Foo Regulars||Foo Newbies|
Extroverts should have a grand time, lots of people to talk to. Regular attending introverts can lean on existing acquaintances when burnt out. But if you, like me, are an introvert, and you aren't part of the "in group" of repeat attendees, you may find yourself feeling socially isolated and very very tired, in the midst of a happy group of very energetic people. You might begin to resent them.
Foo is what it is, though. It is an opportunity to connect with some people you'd otherwise never meet, so all you can do is arm yourself before-hand with some tools and expectations to avoid having a negative experience.
First of all, bad news, the Cocktail Party dynamic is going to be a major mode of interaction. "So, what do you do?" You're going to have to answer that (and ask that) a lot, and people will filter you based on your answer. It's best to have an answer that is interesting to a wide swathe of people outside your field. The population of askers will be intellectually sophisticated (Michael Arrington excluded) so the answers that generally work can be surprising.
For me the general truth "I work for OpenGeo doing spatial database programming" was not effective at all. But a specific instance "I'm working on spherical geometry algorithms for location data" worked pretty well. (Unfortunately I was too dazed to really parse that fact until after I left.) Anyhow, on review, the second explanation has lots of potential follow-ups from "why?" for people who understand "location data" to "what's that?" for people who don't. The first explanation is too mushy.
Back to the bad news. Because a lot of your interactions are going to be draining first encounters, you're going to run out of gas pretty fast. Find a seat by the fire, get a quiet corner, and don't feel guilty about not talking. You're tired. You can't. Go to bed early, it's OK – the alternative is just going to make you feel worse.
Note to Parents: Your early-to-bed-early-to-rise conditioning comes in handy sometimes. You can get up early, get a coffee, and join the other parents for a quiet, introvert friendly, discussion around the fire pit while all the 20-something future masters of the universe are sleeping off their hangovers.
The "Formal" Program
Sessions are easy. There's structure, you can talk or not. For a first time attendee, I think this piece of wisdom on the Foo wiki ("Find people whose work you have no supposed interest in and go to their talks" -- Chris DiBona) is absolutely wrong.
You can bring the most value to the group, and meet the people who are going to be of most direct value to you in the future by going to sessions that are directly interesting to you, that fall in your area of expertise, that you have passion for. If you're going to Foo over and over again like Chris, then you have the luxury of sampling. I (foolishly) took the advice and missed going to database sessions with folks like Brian Aker, who says something worth writing down (if you're a database geek) about every 30 seconds. Bad, bad decision on my part.
Blowhards: There will be blowhards. Statistically speaking, the larger the session, the more likely there will be a blowhard in your session. Scott Berkun's 2009 post mentions them, and I like his idea of the "anonymous gong" to help the blowhard achieve self-awareness.
Bring a Pen and Paper
Laptops and iPads are heavy and take time to start up and get into data entry mode. Paper is light and fast. There will be names and ideas you want to remember. Precisely when the nuggets fall from the sky is unpredictable, but you probably won't be sitting down with your device at the ready.
Own your inferiority complex. Yes, you're inferior. Suck it up. Unfortunately, this is "do as I say, not as I do" advice, because I wasn't very good at it.
I didn't tell Kathy Sierra that her 2009 Business of Software talk is currently conditioning all my thinking about building the OpenGeo Suite materials. I just glanced at her out of the corner of my eye.
I did, however, have a nice time talking with (well, listening to) Mitch Kapor. Feed them some rope, provide them a context to tell you what's on their mind. A general request for advice on a general topic will usually do. I asked Kapor about economic development. I should have asked Sierra about our own product issues.
Invisible Celebrities: I actually talked to Chad Dickerson, but I never connected the dots until afterwards that he wrote the "CTO Corner" column in InfoWorld, back when it was a paper publication. That column was the only reason I kept receiving the magazine, it made me feel sane (I am not alone!) to be advocating open source, which was very much a minority position at the time. I would have liked to have told him that.
Meeting People You Want To Meet
If you look at the list and see a name you absolutely want to meet, track them down ahead of time, get their contact information and then contact them during the conference and arrange a time.
The venue is deceptively intimate, but 250 people is a lot of people. You may not randomly run into the person you are looking for. You probably will not. I was absolutely looking forward to talking with James Dixon about open source business models. I even staked out the main passage ways, during transition times. I did not see the man! (Here's where having one of those "iPhone" things would have been handy.)
Surprising Social Norms: Either there is a Silicon Valley thing going on that I'm not acclimated to, or this behavior is a form of status advertisement for high status individuals, but a number of times I saw people pull out their smart phones and check messages while other people were talking to them. I had not encountered this before, though I suppose it is just a variation on the equally noxious answering-your-cell-phone-in-the-middle-of-a-conversation. (Both should be grounds for an immediate caning.)
Us and Them
People sometimes ask, "What can I do to be invited back?" and your best bet is to make a (positive) impression by engaging and presenting.In general, it's going to be hard to make a good impression if you have no psychological energy. And it's difficult to plan for a session or an Ignite talk when you have no idea what the audience is going to find interesting.
— Foo Camp Wiki
However, having seen the audience, I can now (post-facto (arg!)) offer a generic recipe for an interesting topic: something that is foundational in your specialty field but mostly unknown in the larger world. In my case a talk about general principles of geography, like Tobler's Law or the ecological fallacy or some topical examples of how to lie with maps would have gone over well at Ignite.
It's worth noting, given the mix of regular repeat attendees versus new attendees, that the criteria are not strictly meritocratic — obviously you can also get invited back by being intrinsically "important" in some way to the O'Reilly organization. The "engaging and interesting" criterion is only applied to some.
Like many of life's memorable experiences ("there was this time I hiked to the top of a mountain in the rain…"), there is a strong possibility that, as an introvert in a highly social milieu without a group of friends to lean on, you might find Foo Camp difficult and unenjoyable in the moment. You might want to leave, a lot of the time. But if you stick with it, you'll come out with some good memories and look back on it as an important experience. You'll also meet some very friendly people who will make you feel welcome despite yourself. Give it a shot.
Shout-out: Thanks to the people who made me feel not like a stranger at Foo Camp, despite my acting like one. Selena Deckelmann, Cary Davis, Joe Hughes, Matt Cutts, Nat Torkington, Shel Kaphan, Toby Boudreaux, Andrew McLaughlin, Laurel Ruma, Emily Jacobi and many others.