Sometime last year, I read some columnist urge the reader to build a "digital ark" in an era of increasing censorship. I thought it was a good idea, and started (if lackadaisically); but more recently I realized a flaw in my method. I imagine many have already noticed this.

Although some of my stuff is downloaded from PG, most of my e-books are purchased online through a certain bookseller (no, not Amazon). They're not stored on my computer, they're stored on the company's server. That is a problem, because the company knows what I have access to and, if at any time they decide they don't approve of it, they can take it away from me.

Am I right that this is an insurmountable problem if I continue to purchase e-books from vendors? I'm stuck?

The only way is to own your media. In my case for video / music if I can't get a physical disk (dvd,cd) then I don't have it (exception to music below). We don't buy anything on streaming services that they can disappear whenever they want. I have no Apple devices, and if we did I wouldn't really want my family to buy anything on itunes. It's perfectly fine if they can get the .flac or .mp3 but that isn't how it works. I have bought plenty of digital music in .mp3 format from Amazon but only because I could download it and control it in my server. If they DRM it and I can't get it without going through their player or authentication bs then I will no longer purchase from them.

That is the only way. If you don't have a copy that isn't dependent on their software or servers then you don't actually own it and it is at risk.

That being said... I don't think it's a likely scenario statistically. Incidents like you describe are extraordinarily rare. The legal issues to it are immense at least in the US. Of the few cases I've seen like this they usually end up giving back access. To much bad PR. As such many have changed their terms of service to say you are buying a revocable license, not the actual media itself to get around it but it's still a slippery slope either way.

Conceded: there is an enormous length of slope between the currently trendy forms of censorship, and censorship of books. And there's already some pushback against what new censorship there has been.

Buy your ebooks direct from the publisher or author, or from independent stores like Smashwords. You can often get them DRM-free and multi-format that way.

Agreed with jmgibson1981 - if you don't have a 'non-DRM' or 'physical' copy you don't have a gurantee of control/access. That doesn't mean you're trying to pirate something, just in your example with a 'digital store' the rights could cease to exist ('censorship' may be a part of it, or the company could just not re-negotiate rights to a given set of media assets - think about Netflix and Disney for example, where Netflix at one time offered Disney-owned things, but no longer is able to get them because Disney wants to offer a competing platform), but the bigger concern I have is the company itself going away or moving to some format/model that is incompatible with devices you may have - so say they require accessing the books you've 'bought' via an app which currently supports an OS you use, but say in 2-3 years they update it and thats no longer an option, and there's no backwards path. This has happened to some games, for example like Rocket League, which was ported to macOS and Linux, but the developer updated and discontinued that support - buyers still technically have rights to the new version of the game, but it requires Windows to run it.

The *other* thing with having a non-DRM/non-app-locked version of whatever media is it usually allows for offline or mobile access - if you have an epub of a book, for example, you can put it on any device that can read that, without needing to be connected to some cloud-based 'viewer' application that streams the data. With books the data involved is pretty minimal, but with video or audio the data involved (in terms of bandwidth) can be substantial - maybe not practical in certain settings (like say you're going on a roadtrip or a long flight).

No data I have online is considered sacred. If I lose it (get locked out / hacked / account delete / censored), no big deal. No matter what their privacy agreement says, I don't trust any company not to snoop my data. Not that I have anything they'd find interesting, anyway.

The sum total of my 30+ years of collected data is less than 1TB. I have two external 2TB hard drives that are exclusively for my backups. I alternate between them about every month (which gives me a 2 month grace period in case I accidentally lost/deleted something important). I also have older, but semi-recent backups on various thumb drives.

The only thing I'm missing is offsite storage. If my house burned down, I'd be in bad shape.

One thing I'm concerned about, given the nature of new cloud OS architectures, is that some time in the future before I die (which I hope is a long time), it'll become difficult to continue keeping offline storage. Old hardware fails, how many more years before local storage (hard drives) goes the way of the CD?

I doubt this will happen very rapidly - most systems seem to encourage users to make offline backups these days, for example if you plug an external hard drive into a modern Mac it will ask if you'd like to configure it for automatic offline backups, and (at least the last time I used it) Windows will encourage you to setup some sort of offline backup to external disk or DVD-RW during initial configuration. I haven't seen such automated requests on linux (and wouldn't expect to in Xfce), but I know GUI utilities exist to facilitate it (and some distros even enable/encourage you to build your entire working image as a 'backup' - for example PC Linux OS and Puppy both do this). I highly doubt we'll go 'back' to some sort of distributed terminal/mainframe model - the local device still needs storage and compute capabilities even with modern cloud services.