I would love to see an ActivityPub implementation of a decentralised library of things. You could post things you have and like to lend, add location and availability. Others could comment, like, boost and inquire.
Edit: of course trust is a huge part of it. But social media (friends of friends etc.) is the perfect fit imho.
This is the important part to understand the difference between lets say the „European system“ vs. the „US system“:
In the US the Democrats and Republicans each encompass big tents that hold several groups that would otherwise be their own political parties.
The US negotiates the different political streams within one of the two parties before the elections. Whereas in most European countries these negotiations happen after the elections in coalition building. Have a look at scandinavian elections and you will see blocks that can be interpreted as a hybrid form.
As a native German and antifascist leftist I'm worried as well, but I don't think that history will simply repeat itself. The problems we are facing are very different and I don't think that a party as radical as the AfD is able to gather 20% support in a federal election. Germany HAS become a multicultural wonderland in recent years and the majority supports it! German politicians of the left, center and center-right shouldn't engage in the blame game. Especially the CDU/CSU has to understand that their role now is not to copy AfD talking points.