I have a pretty low attention span, but know the answer to several of those questions without even having to go back to the page (though I will, for the sake of argument). This might not be the case for everyone, but for the way I consume information, the product is described pretty well.

    1. What OS is this whole thing running?.

Listed under "storage" section:

    OpenZFS + CentOS 8.2   (maintence support until 2029)
    OpenZFS + Ubuntu 20.04 (maintence support until 2025)


    2. How many drives do I get? What’s the point of ZFS on a single drive? Is this just a way for me to temporarily hold a file system?

Listed under the "storage" section:

    We rent out KVM virtual machines with dedicated 8-TB hard drives.

Listed under "pricing model" section:

    Rent out multiple drives if you wish to create a RAIDZ or Mirror ZPool. 


    3. I don’t remember all the flags for the various zfs/zpool commands so the example command means little to me. This seems to be the main thing explaining what the service is for, yet I would have to go and look at the man pages to figure out what it does. Best I can tell: I can send my whole filesystem from my local NAS to my drive in the sky, but why would I want to do that?

`zfs send` isn't exactly an exotic command, and while I can't blame you for not knowing each and every flag, does that matter? The site clearly states that you have a raw disk passed through to a KVM machine, which is pre-configured in a storage pool, but that you can configure it however you wish.

    4. Why do I get root access to the box? And if that’s the case, why do I need it?

I agree that the unmanaged aspect of the service should perhaps be more prominently highlighted, but the site clearly states that you configure the machine however you like. To do that, root access is needed.

    5. What are the details of the data center they are in? Or the location? Or how did they arrive at their 99.999% reliability? 

I agree that more information about the data center would be relevant. The location of the DC is listed under "set-up time" section (Sacramento).