You can do opens source without being OSI compliant. They don't own the concept. As long as the source is readable, it is open, even if you can't redistribute it, or distribute a binary built out of it.

In this case:

http://creativecommons.org/licenses/by-nc-sa/2.0/ says that

    You are free:
      * to Share — to copy, distribute and transmit the work
      * to Remix — to adapt the work

    Provided that you (paraphrased):
      * (BY) — give proper credit to the original the author,
      * (NC) — don't use it commercially,
      * (SA) — publish your modifications with the same license.

Beside the non-commercial clause, when applied to source code, it is roughly equivalent to a BSD/MIT license.

The BSD and MIT licenses make no mention of commercial usage? The NC clause is exactly what makes it incompatible with all FOSS licenses.

> Beside the non-commercial clause, when applied to source code, it is roughly equivalent to a BSD/MIT license.

More like the GPL, SA is CC's copyleft.

Yes, "open source" is not a protected term, nor a trademarked term, so anyone can call anything "open source".

However for lots of people who deal with software, calling this "open source" is highly misleading and at worst disingenuous. Within the open source software (and wider software world), it's quite clear and non-subjective whether software is open source. There are numerous, nearly entirely harmonious definitions of "open source". Under those rules, within that community, this is not "open source".