Decentralization of personal data storage – particularly through self-hosting – is one of the easier – and more effective – things we can do right now as "regular" folks to help.
Not just in terms of [insert current crisis here], but in generally getting our society and information back under individual and community control.
Why? It’s pretty simple. Remember that story about Target predicting a teen girl’s pregnancy? It was probably exaggerated (at least) back in 2012, yes. But I think that it’s a valid concern today.
That story was ten years ago, or about five forevers ago in Internet Time. Even if the original story is exaggerated, there are significant obvious economic reasons why that kind of technology would be refined over the last decade, and the results kept under wraps.
Second – and perhaps more terrifying in these trying times – is that such technology would still be dangerous in identifying people of interest. If you’re trying to identify possibly pregnant people out of the general population, even ten-year-old code would still narrow the field greatly, making more in-depth investigation by humans much more feasible.
I mean, sure, the big companies pinky-promised that they wouldn’t share that information. And I’m sure you can trust them, right?
So why aren’t decentralized services and self-hosting more common?
The problem is that decentralization – particularly through self-hosting – still isn’t easy. It’s a lot easier than when I started forever ago, thanks to container technology like Docker, dynamic DNS, and the ease of VPS hosting, yes. But easier is a relative term.
So it’s up to us homelabbers and selfhosters – those of us who do know how – to make them available for our first and second level contacts and friends. Not only will this help protect our friends, but it will also help increase the knowledge and popularity of the software and projects we care about.
Here are some of my suggestions of services to run/host to aid your local community, and some non-selfhosted but privacy-respecting alternatives. This is not an exhaustive list; there are a LOT more really cool self-hosted projects collected in the Awesome-Selfhosted list.
Set up a Flashpaper instance
The point of Flashpaper (or Shhh or Hawkpost and others) is to provide a way to share "burn on reading" encrypted messages easily without having to teach encryption. Type your message, get the link, send the link via e-mail or chat. Once it’s read the first time, it disappears. I personally chose Flashpaper because it’s super simple to set up via Docker, and super simple for the end user as well. There’s a demo of Flashpaper at https://flashpaper.io/.
Set up a CalDAV/CardDAV server for you and your pals
There are a LOT of different options for setting up self-hosted calendar and contacts sync, ranging from bare-bones with no web interface to entire groupware solutions. This is particularly important since right now there’s a lot of concern about tracking personal medical data without giving that information to an app or third party company. Once you have the server up, your friends can set up a separate calendar for that data on their devices without having to move everything else.
I’ve heard plenty of good things about Radicale, but also consider your (potential) users and ease of signup and use for them. Personally, I found Nextcloud  to be a good compromise between security and ease of use. Additionally, if you use the External Sites app, you can link to other self-hosted (or privacy-respecting) sites for your pals.
If that’s too complicated, Tutanota has its own privacy focused groupware (email, contacts, calendar) suite and apps.
Set up SearX or Whoogle
If your friends won’t just switch to DuckDuckGo, install and introduce them to Whoogle. Whoogle is a privacy-respecting front-end for Google and is VERY easy to set up and install, with a familiar interface.
Set up your own PGP/GPG key and get it on keyservers
Look, if we want encryption to be more commonplace and accepted, we have to ensure that we have our stuff set up first, particularly since there can be fiddly bits in getting things set up.
While there were/are issues with the "SKS pool" , the keyservers at keys.openpgp.org, keys.mailvelope.com, and keyserver.ubuntu.com are not part of that pool and are solid. My GPG key is available at all three (keys.openpgp.org, keys.mailvelope.com, keyserver.ubuntu.com).
 Disable "Circles" for privacy reasons, minimal file space per user, and turning off all federation and sharing, and using the "RegistrationRegistration" app to allow email signups.
 If you don’t know what that means, don’t sweat it. TL;DR: old method that turned out to have several unpatched weaknesses.