Recently I've become aware of more and more tools that allow people to solve puzzles online. For many years there have been a collection of websites (nikoli, fed, croco, kwon tom loop to name but a few of my favourites) that have allowed.
However there are also a rather more versatile set of tools that are available to use. These allow you to mark up versions of various puzzle types from a blank canvas, and also allow you to then further solve the puzzle. Some will even helpfully tell you when all constraints of a puzzle are met, and that the puzzle is solved (although this approach will not tell you if there are more than one solution to a particular puzzle).
What this means is that in some sense, a link is now equivalent to a published puzzle. People are now able to share a puzzle by taking a bit of time to mark up the initial clues, and then by sharing a link.
For example, here is the first puzzle I ever put on this blog:
My attitude to copyright and getting my puzzles out and about in the wild has been generally quite relaxed. Although in theory you could scrape the images of my puzzles, the images themselves have a reasonably distinctive style so that if ever anyone wanted to abuse the conditions imposed by the licence I use, then it would probably be as the result of a mistake and something that would be easy to fix.
Things like the PZV tool change the game slightly. For one thing, my visual style gets lost in the generic house style, and this is a house style that is shared with hundreds, maybe thousands of other different authors. That link in isolation has almost no indication that the puzzle it features has anything to do with me.
As others (such as GM Puzzles) have pointed out, when you use this link, you are stuck with this house style. There is no room to customise the solving page with useful metadata that might come with the puzzle, such as the name of the author, a particular series the puzzle is part of, links relevant to the author, copyright statements, licence agreements and so on. Perhaps you could view this as just extra red tape and bureaucracy that gets in the way of solving and sharing puzzles, but there is also a danger of taking the authors for granted here.
More than this, whoever is in control of the hosting of the pzv.jp server presumably has a list of links that people have accessed on this server. Given the equivalence between a link and a puzzles, it would not be too hard to take those server records and create a database of puzzles that are essentially the intellectual property of other people. Of course, if you are an author, then you can take your chances with that and make your own decision. However, the ease and convenience of this might mean that well-meaning third parties might take it upon themselves to do this without the knowledge of the author.
I think as far as I see that kind of behaviour, in my mind creating and then sharing a link is equivalent to republishing the puzzle. So I suppose one thing I'd like people to bear in mind is that if you are going to create playable links for any of the puzzles published on my blog, then you must abide by the terms of the licence. So you must also provide attribution, you must also provide a link to the licence and it must also be for non-commercial purposes. I think it would also be common courtesy to let you me know that you've created the link, so that I'm at least aware that my puzzles could potentially be logged on a server completely out of my control.
Things like puzz.link change the game even further. Puzz.link does a few different extra things. Firstly it maintains a database of publicly available puzzles which have been posted as links, scraped from either: (a) web sources such as blogs, which have presumably agreed to have been scraped, or else (b) scraped from twitter links. In either case a link to the original post is maintained, although everything is presented in the puzz.link house style. The second thing it does it allows a user to log in and effectively have a record of all the puzzles that they have solved within this public part of the database.
The third thing it does isn't really described adequately in my opinion, not least because the source code for this database is not currently published, in contrast with the puzzle solving applet, which is published. As far as my understanding goes, every time any user solves a puzzle means then a communication is made to the website with details about that puzzle - regardless of whether the puzzle was linked to from the public database, or whether it was created by some third party, and perhaps without the knowledge of the original author of the puzzle.
This essentially means that this database is much bigger than the public front accessible from the website, and contains plenty of metadata about puzzles that are not publicly available, and presumably also an equivalent form of that puzzle. Quite what I make of what is presumably a much larger than advertised database, I do not know.
The privacy puzzle for puzz.link says that:
For all puzzles shared via puzz.link, the copyright lies with their authors. We merely serve an interface for solving those puzzles; any issues should be taken up with the site hosting the link. The puzz.link database only shares puzzles that are available publicly, and links to their source.
However whilst puzz.link only "shares" puzzles that are available publicly, it still keeps a private record of puzzles that the authors may not have intended to end up on the server. Presumably puzz.link would be OK with a request from an author to remove any links equivalent to their intellectual property from this database? Approaching this problem this way around feels a bit problematic to me, because very plausibly an author might not know these equivalent links even exist within the database - effectively they would not be public by definition. This ends up sounding very much like a paraphrased Facebook/Google-esque defence that "we are just a neutral platform independent of the content posted on our platform", and I don't think that sits entirely comfortably with me.
Anyhow, as I said at the top of the post, I am still unsure exactly how I feel about this all, not least because much of what I have posted I do not have a full understanding of. There are clearly some very big positives that I haven't talked about as much here, but there are also some drawbacks, and I feel the positives are being talked about far more than the drawbacks.
There are a few other thought experiments to think about - for example the links are only of any value because of the underlying applet; what changes if you had an image parser to do exactly the same with the png images that already exist on this blog? - but perhaps I'll leave further discussion for any comments.