Archiveteam's Reddit project is working to save reddit content from the hungry maw of corporate destruction.
Archiveteam (AT) is a group which according to their website,
is in no way affiliated with the fine folks at ARCHIVE.ORG
However, the goals and philosophy of archive.org, aka The Wayback Machine, aka The Internet Archive do have significant overlap with AT. AT is coordinated by a staff member of archive.org, and the products of their work are typically donated to archive.org.
They do missions to save particular collections of internets which are under imminent or generalized threat of deletion. One way to participate is by installing their custom Warrior VM software on your computer and it will use your home internet connection to pretend to be a user and systematically crawl/save the material in a coordinated fashion which evades detection.
There can be other tasks if you can't or don't want to run that software. For example if the Warriors are triggering captchas, they can forward the captchas to users who sit around solving them. So you can solve captchas on other people's computers so those computers can proceed unattended.
Here is the tracker showing the moment to moment progress. At time of writing it display 13.58 billion items weighing in at 3.06 petabytes (3,060,000 GB).
Here is a reddit post from a month ago going over this specific project.
You can find more comprehensive info on their website. They coordinate via IRC.