For at least the next 10-20 years there will be a shortage of developers who are able to build the future. How should the developer community determine what projects are worth building and which ones are not?
Great question! Although I don't think we'll get the answer in this thread, I do think that we are deciding what to do and what not to do on a daily basis in communities like Hacker News.
Communities have the power to create a popular culture which can guide the loosely connected membership. My answer isn't a complete cop out :)
That said, I think the future is in making our access of the web more invisible. We need to focus on finding simpler ways to access the internet and open protocols between devices that allow them to communicate and authenticate us seamlessly.