As users, we're all familiar with the idea of lock-in.
A service starts. They offer something attractive. We use it. And later find out that we can't move without leaving behind everything we created there.
Lock-out applies to developers.
A service starts, offers something attractive to users. But it has no API. It can't share its data with any other application. It can't receive data either. If a user wants to create something, they have to use their editor. And if they like the editor, they can't use it to create something that lives elsewhere. The creation and serving are bound together in a closed system. No other software can enter.
A system with APIs is part of a network of software. One without APIs stands alone. If you get an idea for a feature that would make a world of difference, you can't implement it unless they offer you a job, and once inside, let you do it. And don't cancel the project before it's done. And it isn't taken over by someone else in a organization shift. There's a reason big companies don't create new stuff, they are subject to rules that individual creators aren't. They aren't free to try new ideas out.
I guess all industries have lock-out. The moneyed people own everything, and in order to create, you have to fit in. And most really creative people don't.
Then you have systems that are not locked-out, like Twitter and Facebook, but are subject to revision at any moment. This is imho better than not having APIs at all. At least the world can get a glimpse at the idea before it's shut down. In a fully locked-out system, new ideas are stillborn.
The good news is the costs on the net today are so low that there really is no technologic or economic reason for lock-out. And so many developers want to make open source contributions. It's really just a matter of organizing the work to create open alternatives to the locked-up systems created by the tech industry. We need user-oriented frameworks for free systems. This is the one area where open rebellion is not only legal, it's encouraged. At least if you listen to and believe the proponents of free markets. We're going to find out.
I wrote a story on my liveblog on Monday about my personal experiences with lock-out.
Also see an offer I made to Medium when they started, in 2012. They could lead a new wave of silo-free writing for the web.