Not attending. Big waste of time and money. I don't want to spend that much money for airfare, a ticket to the conference, and hotel/food fees just to watch Zuckerberg reveal something I won't use and to talk to developers for help I can get on Stack Overflow for free.
First, all conferences are expensive in terms of time and money. That's a given.
> just to watch Zuckerberg reveal something I won't use
I think you're overlooking the value. It's not about going for a keynote or being entertained/catered to; its about the interaction. The ability to talk to the people that've built the tools you are using is extremely powerful. Would you rather talk to an expert on a subject matter, or post a question on SO and hope someone has had a similar experience? This is just one of the reasons why conferences like this are "worth it".
> Would you rather talk to an expert on a subject matter, or post a question on SO and hope someone has had a similar experience?
Personally, I would rather that people post their questions - and then receive the answers - somewhere that's easily searchable, so that when other people have the same questions they can easily find an answer. There is certainly value in increasing the number of experts, though, so perhaps that's what you were pointing at.
I was alluding to the fact that talking directly to a FB dev to get or give suggestions is extremely valuable. Especially when speaking on non-trivial topics.
FYI even at $400/ticket, Facebook are almost certainly losing money on putting on the event.
$400 is that interesting price range where it will be a 'big waste of money' (as one other commenter put it) to anyone who isn't otherwise directly involved and profiting from the Facebook platform ecosystem.
How are you able to say that they're losing money at $400/ticket? This is a one-day conference. $400 times maybe 4000 attendees = $1.6 million. That should be plenty to pull off a one-day conference.
Moderate success? Every major web site out there has like buttons plastered all over their page. I'd say that the Like button has experienced phenomenal succcess, especially in terms of what it gives Facebook.