Not quite a CAPTCHA, but something similar has actually been done before.
The ESP game[1] paired two random people looking at the same image while a timer ticked down. The players had to enter labels that described the image, and if both players applied the same label, their score increased, and the label was associated more strongly with that image.
Well-known labels for an image were excluded after a while, so you had to guess less and less obvious labels in order to score as time went by. Once in a while the system would also assign test images with known labels to prevent cheating.
Apparently a lot of people played it because it was fun, so there wasn't even the need to pay them for labeling the dataset...
Something similar exists: iabackup[1][2]. It is designed to host an independent copy of (some of) the Internet Archive using git-annex. You tell it how much storage you want to donate and git-annex fills your disk with data from the least-seeded files IIRC. Its focus is on data backup, not data serving though.
I've been looking for software that does this myself, but I don't think it exists.
There used to be a project, https://bazil.org/, that promised to do it. The website is still up, but it has not been updated in years.
The existing tool closest to what I envision is git-annex. It tracks what files live where, and you can sync single files or as much content as will fit on the local harddrive with a few commands. There is also git-annex-assistant for a more dropbox-like experience, although I haven't used it myself.
> RancherOS is the smallest, easiest way to run Docker in production. Every process in RancherOS is a container managed by Docker. This includes system services such as udev and syslog. Because it only includes the services necessary to run Docker, RancherOS is significantly smaller than most traditional operating systems.
The obvious way to do it would be to forward a port in your router and then keep a dynamic DNS service (DuckDNS, for example) updated with your external IP address.
As for networks, I personally use the Yggdrasil Network [1] to connect to my homeserver. Since it is a self-contained network, a blog hosted on there wouldn't be visible to the web, but it's very, very convenient for private access. It traverses NAT without any hassle once you connect to other peers.
If you do connect to the network, you probably want to also set a whitelist of peers that are allowed to access your machine, otherwise it is open to the entire network.
The ESP game[1] paired two random people looking at the same image while a timer ticked down. The players had to enter labels that described the image, and if both players applied the same label, their score increased, and the label was associated more strongly with that image.
Well-known labels for an image were excluded after a while, so you had to guess less and less obvious labels in order to score as time went by. Once in a while the system would also assign test images with known labels to prevent cheating.
Apparently a lot of people played it because it was fun, so there wasn't even the need to pay them for labeling the dataset...
[1]: https://en.wikipedia.org/wiki/ESP_game