A fan of the practice (unconnected with SynergyExplorers.org) has set up a makeshift dating app for those interested. Here are the instructions, which appeared on r/karezza.
The app is called Boo; it’s a free dating or friendship app that lets you filter users based on interests and request interests to be added to the app. Unfortunately, I tried for a few weeks to get them to add the #karezza interest, but they rejected it because it violated their guidelines somehow (perhaps too overtly sexual). However, they did just approve the #synergy interest, which is essentially another name for karezza.
So, to use this as a makeshift karezza dating app, all you’d have to do is:
Download Boo on the iOS or Android App Store
Sign up for a free account
Add the #synergy interest to the interests on your profile
(If you want) Set your preferences to include only users with the #synergy interest: here’s a quick visual walkthrough
Someone asked how you designate “Synergy” in the browser version. Reply:
The same way as the mobile app, once you log in at app.boo.world. If you’re not logged in, it looks like the browser version just shows a big feed of posts. (Boo lets you make posts for an interest, too.) Here’s all the posts for synergy (there aren’t any yet).