Note: While we are working on the details of the ARCHMAGE Engine Trademark License, please contact simonwork@profantasy.com if you want to create independent 13th Age compatible supplements. You don’t need our permission to do so, but he can offer helpful advice and guidance.

Rob Heinsoo’s original article on licensing follows.

A creative flame.

Arcane mastery.

A hint of guile.
We’re creating 13th Age under the Open Game License because we think the OGL is the right way to play well with others.
We are working out the interactions between Fire Opal Media, Pelgrane Press, and people who want to publish things related to 13th Age using the OGL. As a result, some of what I’m about to say in this post may change, but in broad outlines, here’s what’s going on. Those of you who care less about technical details may find your eyes glazing over the deeper you go, so I’ve tried to put the good stuff on top.
Right now, people who want to use our game mechanics can use them so long as they comply with the OGL. It’s sweet to ask us permission and tell us what you are up to, the way the folks using using 13th Age mechanics in the Last Stand and The Bestiary of the Curiously Odd Kickstarter projects did; but you technically don’t have to ask us permission to use the mechanics.
So if you want to publish your setting and your original icons with our mechanics? Go for it, and use the Archmage Engine logo above (thank you, Lee Moyer!) to identify your work as being compatible with 13th Age.  You can also say “Compatible with 13th Age” on the cover of your book. However, the 13th Age logo itself is part of our product identity, and therefore not available to use without our permission.
For a while at least, only Pelgrane Press will be producing 13th Age RPG supplements which use 13th Age product identity.
People who want to publish professional material such as magazine articles that makes use of our product identity material in 13th Age will need to ask Pelgrane Press for permission. Email Simonwork@profantasy.com. This permission applies to both initial permission to do the work and final approval of the text. Magazine articles, for example, fall under this category, and are likely to be published with a line saying something like
13th Age and the Icons [plus other elements that might be in the article] are trademarks of Fire Opal Media. This article published by agreement with Pelgrane Press Ltd.
Using our artwork with permission might also be possible, and if used would include a notice like so:
Artwork copyright ©2012 Fire Opal Media Ltd
Shortly after 13th Age is fully published we will publish a System Resource Document to help people sort out which parts of 13th Age are open game mechanics, and which parts are product identity that can’t be used without written permission.
The SRD will sort through what are open game mechanics and what is our product identity. A starting point is in the notice at the front of the Escalation Edition of the game, which presently identifies our product identity as: All trademarks, registered trademarks, proper names (characters, icons, place names, new deities, etc.), dialogue, banter and comments from Jonathan and Rob, plots, story elements, locations, characters, artwork, and trade dress.
We’ll also come out with some form of friendly policy statement to allow fans to talk about and use our world and setting details on blog posts and fanzines, without having to worry about asking permission. I don’t know exactly what that statement looks like, but picture something terrible and restrictive and then imagine the opposite. We’ll do the opposite.
If there are aspects of the situation this blog post didn’t cover, wiser heads will deal with them shortly.
…and for the souls who perceive the oddities of OGL interaction with product identity, yes, it is a tiny bit odd that we’re using the symbol of the Archmage, which is otherwise part of our product identity, to anchor the logo for the game’s engine. But what the heck. The symbol looks good, it should communicate to players of 13th Age, and given the enthusiasm we’ve seen from Team Archmage we’re happy to share the symbol in this respect.