Sadly, APIs are not the solution.

Web 1.0:

That guy is bright. He knows everything about the solar system. You can ask him any question about it, and chances are that he knows the answer.

He's also quite good at explaining this stuff, and it's much more accessible than reading these complicated books about space.

He won't listen to others, though. He only trust his books.

Web 2.0:

That girl is popular. She has so many friends, and she's always the first to know about any gossip. Heck, that's all she does.

Tell her something, and it's quite likely that the whole school will know about it the next day. She keeps track of every rumor in her journal, to make sure to remember every detail.

She's a bit naive, though, and tend to believe every rumor she hears.

Web 2.5 (APIs):

That guy is serious. He doesn't play games. You want something? He'll make sure you get it.

Don't bother calling or meeting him though, it's not worth his time. Here's a form you can fill to let him know exactly what you want. Sure, it looks a bit complex at first sight, but you'll get used to it. The first time is always the most difficult. You can call his assistant if you need help filling the form, though.

Once you hand him the form, it's a matter of hours before you get what you asked for. He's that fast.

Web 3.0 (semantic web):

Where is everybody? That's right, they're all at the bulletin board. What is it you ask? It's where all the cool kids hangout.

Want to let the world know something? Anything? Just pin something there. You have to follow the rules, though. You can't just write some gibberish on a piece of paper, you must communicate using the proper syntax, and learn to call things by their unique names (nobody's going to take you seriously if you make some ambiguous statements).

Once you learn the drill, though, it's fantastic. You can find ANYTHING you want there, as long as you know how to navigate it. No need to ask anything to anyone, no need to learn a bunch of different ways to say the same things (it's so annoying when that other astronomy kid use different terms to describe the same thing as the first guy I told you about). I used to be limited by what individual people I met wanted to talk about. With that board, there's no such limit. I can communicate anything, get there the next day and see an answer.

"The only limit is yourself" - Zombo.com

Conclusion:

The web 2.5 (API web) is limited by what the service let you do. You want to do something that is outside the scope of that particular service? Too bad, you gotta create your own company and ultimately face failure.

These services are too rigid (lack flexibility), they're opinionated and non-standard (you have to learn every service all over again, 10 extremely similar services will have totally different APIs and ways to call and model things), and ultimately, you have to level-down your solution based on the limitations of the service. It's not a proper way to live.

Sure, it's nice and all that we agreed to all communicate using voice and ears, but we still all speak different languages, and having to learn the language of anyone I want to talk to is painful.

We must unify semantics, not just the medium (JSON/XML). Over are the days where you model your classes yourself.