[jpetazzo]

There is a trade-off between "running anywhere" and "running mostly anywhere". I.e. going from 99% to 99.99% :-)

The server-side component only runs on Linux for now, and while it's supported only on x86_64, people have confirmed that it could run on i386, and arm v6/v7/v8.

Later releases will also target FreeBSD, Solaris, and possibly OS X.

The client-side component already runs on OS X, and could possibly run on Windows as well.

However, there is currently no interest at all in running Docker on AIX, HP/UX, Plan9; or on Sparc, Power, s390, or Mips platforms.