First new year’s resolution, 10 days late: I will use ‘hereditary license’ any time I am tempted to say ‘viral license.’
Surprisingly, this generated quite a few responses (on identica and elsewhere)- some people liked it, but many people had their own alternative to propose. So here are some longer-form thoughts.
There are four primary options that I am aware of when trying to find a one-word term for open source licenses that in some way compel distributors to also distribute code- i.e., the licenses called “copyleft” by those of us who have spent too much time with this stuff. The terms:
- Copyleft: This is the common name when speaking to other people experienced in open source, so it’s obviously the first choice when you know your audience has at least some experience in open source. But to an audience not already involved in open source (the only time I’m ever even vaguely “tempted to say viral”), the phrase is completely non-obvious. It has zero evident meaning. In fact, it can actively confuse: it could mean the reverse of copyright, which to most people probably means “no license” or anti-copyright altogether. So it’s really not a good word to use for audiences who aren’t familiar with open source- which is to say, most audiences.
- Viral: This is another old standby. Traditionally, the objection to this term has been that it is perjorative: no one likes viruses, so ‘viral’ is often seen as (and sometimes is) a deliberate attempt to frame copyleft licenses as inherently bad. That objection is certainly accurate, but I think there is another problem with this word: it implies that, like a virus, copyleft can spread to someone without their active involvement; you can “catch” it from the digital equivalent of being in the same room with someone, or not washing your hands. This isn’t the case – there must be a strong relationship between the copylefted code and the other code that might be required to be shared. This, to me, is where “viral” really fails to communicate. It makes people think that a copyleft is something that might “happen to them” instead of it being something that they have to be actively involved with.
- Share-alike (or the related word “reciprocal”): Oddly, neither of these is used much outside of the Creative Commons world. Neither of these are bad terms: they are reasonably value-neutral, and they both imply that there must be an actively chosen relationship between the parties, which I think is important. But to me they don’t capture the why of the relationship; it makes it sound like there might be a choice in the matter, or something you do because you’re a nice guy.
- Hereditary: Richard Fontana traced this back to at least 2004, so it isn’t new, but without doubt this is the least used of the various terms I’m discussing here. At least for the moment, though, and for general audiences, I’m leaning towards thinking it is the best option. First, it implies that there has to be a real, derivative relationship between the two codebases; it can’t just happen at random (like viral implies). Second, it also implies that once the relationship exists, further licensing isn’t a choice- you must pass it on to the next folks who “inherit” from you. (Share-alike/reciprocal might imply that you do this because you’re a nice guy, which isn’t the case, or that you do it back to the original sharer- which also isn’t necessarily the case.) The analogy obviously isn’t perfect, most notably because a mere redistributor who hasn’t created a derivative work that “inherits” from the parent work is still bound by the license. But I think on balance that it has the fewest tradeoffs.
So there you go, for the dozen people who asked, and the hundreds, nay billions more who don’t care :)