Personally, I love the idea. I don't have the expansions myself yet, but I think it's great that people can create things like this to even further expand a game that I thoroughly enjoy. (Further, that is, beyond the existing, official 6 major expansions and dozen or so minor booster packs.)
However, I am also wondering a bit as to how they can legally do what they're doing.
Presumably, this is facilitated by the fact that Cards Against Humanity uses an unusually-permissive license for a commercially-sold product of its sort. The game, and all official expansions, are under a Creative Commons license which allows other people to do a number of things that they wouldn't be able to do under the typical copyright licenses attached other works.
In particular, without needing to pay royalties or obtain special permission, other people can:
- Copy and redistribute Cards Against Humanity as-is.
- Make and distribute derivative works that are based upon, and may even partially or fully include, Cards Against Humanity.
However, the particular license used for Cards Against Humanity is CC BY-NC-SA 2.0. This puts the following restrictions upon sharing and re-use of Cards Against Humanity:
Attribution (BY): Appropriate credit must be given to Cards Against Humanity LLC, and changes from the original work must be noted. This should not imply any endorsement by Cards Against Humanity LLC.
Non-Commercial (NC): Any copies of Cards Against Humanity, or derivative works, are not to be used for commercial purposes (e.g.: sold) without permission of Cards Against Humanity LLC.
Share Alike (SA): All copies of Cards Against Humanity, or derivative works, must use the CC BY-NC-SA license or another Compatible License.
Crabs Adjust Humidity clearly meets the BY requirement. They mention several times over on the site that their expansions are not official and they are in no way affiliated with Cards Against Humanity LLC. A notice on their website even specifically states that it is not the Cards Against Humanity website, provides a link to the official Cards Against Humanity site, and encourages people to "Go there and buy it now. We'll wait. Get all of the official expansions, too. They rock.".
The NC requirement is where they most obviously appear to fall short. Crabs Adjust Humidity is being sold, both directly from their own website as well as through other vendors. (Personally, I first discovered the products by seeing them on a shelf at my favorite local gaming store.) Each individual expansion (each containing 112 cards) costs $14 USD, with a boxed set of all 5 for $50 USD ($10 per expansion/$4 off each pack/$20 off the set).
For comparison, Cards Against Humanity sells their main game (550 cards) for $25, major expansions (100 cards each) for $10 each, and smaller expansions for varying prices. There is no official boxed set for Cards Against Humanity. (The Bigger, Blacker Box is - mostly - just a box.)
So, Crabs Adjust Humidity expansions are being sold at about a 25% higher per-card cost than the official major expansions. When you compare the boxed set of Crabs Adjust Humidity to the official main game, the former has a nearly-double per-card price. (Arguably, this isn't an "apples-to-apples" comparison.
* But it was a lot simpler than trying to differentiate costs between Black Cards and White Cards.)
Crabs Adjust Humidity also seems to fall afoul of the SA requirement, as the product (as seen on their Counterfeit Crabs page) and the website have the standard "copyright ... All Rights Reserved" notices. Thus Crabs Adjust Humidity cannot be handled per CC BY-NC-SA, as the license on Cards Against Humanity would seem to require.
Of course, infringement upon copyright (whether actual or simply perceived) tends to not carry consequences unless the copyright holder chooses to pursue them. However, it seems that the creators of Crabs Adjust Humidity (and, as I've discovered while writing this post, about a half-dozen other companies) have chosen to make and publicly sell these works in seeming violation of the CC BY-NC-SA license without much fear of such recourse.
Is this all really legally defensible, or are these products only surviving because Cards Against Humanity LLC has not yet chosen to take action against them?
*Pun not originally intended, but now it totally is.