> It's a question I've never considered before -- should "open" mean "you can API-download everything all the time anonymously no limits", or "you're free to API-download a reasonable amount for consumer purposes with an account, and the more you upload the more you can download"?
Neither, Open should mean that the resources are publicly licensed such that they can be freely rehosted or redistributed. It should mean that the resources are owned by the community rather than the website operator, and that the website should be selling coordination, not access.
Whether or not there's an API limit is irrelevant provided that:
A) the website does not claim ownership over resources it hosts
B) the website is not going to go after people hosting or distributing those resources outside of the site -- ie, users have explicit permission to distribute any and all of the subtitle content on the site
C) there is a way to get the resources off of the site, ie it's not impossible for someone to set up a rehost.
If OpenSubtitles still allows a bulk download or has a mirror, then honestly I don't see a problem with them making this change -- I'm not a fan of it, but if the subtitles are still downloadable in bulk and if OpenSubtitles isn't claiming ownership and would have no issue with someone setting up a separate service or rehosting those subtitles and if (to the degree they can be licensed openly, given that they're subtitles of copyrighted films) they are licensed openly using an OSI-compatible or comparable license in the case of the GPL, then I don't have a problem with them using the word "Open" and I think it still applies.
Having said that, I can't immediately find any information on their website about what copyrights they do or don't try to claim, and it's not clear to me how I would go about building a full dump of the content (a sibling mentions a dump but that it doesn't contain the full subtitles). But that would be my bigger beef. I'm less concerned about whether the website is Open and I'm more concerned about whether the subtitles are Open (again, as open as movie subtitles can be).