[kmontrose]

After thinking on this for a while, I personally doubt the license applies.

Most importantly, it applies to the software (ie. the Perl script; or a compiled version of it) not the "name" or "invention" of Markdown. To own the name, he needs a trademark; to own the invention, a patent. Since Standard/Common Markdown isn't a derivative of the Perl script, the license itself probably doesn't apply.

If he does claim a trademark (registered or otherwise) he hasn't defended it at all for going on ten years now. It's really hard to imagine a court not finding it to be a generic trademark as with Kleenex or Aspirin.

I doubt very much he claims a patent, he's way past any grace period in which to apply for one subsequent to his initial disclosure.

This is one of those "ultimately, up to the courts"-things though. Gruber certainly has standing to bring suit if he wants to.

Disclaimer: I am a Stack Exchange employee. I have not been involved in any of the (now Common) Markdown standardization proceedings. I was aware that they were underway, having read Jeff's earlier blog posts.

[MichaelGG]

As a side note, Bayer lost the trademark on Aspirin (along with Heroin) as a punishment for WWI. But that only applies to some countries. In other countries, it's still trademarked. Heroin doesn't seem to be trademarked at all anymore.