"Being based on open source wireguard, and being just a STUN/TURN server at its core... I'm sure that Tailscale will be the first but maybe not the best."

I like this assessment. "[J]ust a STUN/TURN server at its core." It gives me hope maybe more people are starting to learn how to look at peer-to-peer not as something that is unreasonably complex and off-limits to ordinary users. LAN-like connectivity is not just for offices and gamers.

Of course, following a STUN/TURN standard is just one approach to a rendezvous server. It isn't the first or last approach to have worked.

By "rendezvous server" I mean a program that accepts connections and saves each client's address and open port number and makes this data available to other connecting clients, thereby allowing one client to connect directly to another client without involving the rendezvous server. The server needs only to tell clients about IP addresses and port numbers, nothing more.^1 Thus it can be a relatively small, relatively simple program.^2

I hope that going forward there will be even more choice in small, open source rendezvous servers, not created for commercial purposes, that ordinary users can run on globally reachable IP addresses. Most users must "lease" these addresses from others. Because not every user has a globally reachable IP address available, the use of "hosting" and now what people today call "cloud" services has been necessary.

Enormous amounts of traffic are passing through these third party "cloud" providers. They are, to use a popular term, "gatekeepers". Business customers, including ones who already control globally reachable IPv4 address space, let alone individual customers without such resources, are effectively beholden to them if they want to be on the internet. Not only that, the services are generally expensive.

However no data needs to be sent to or received from a rendezvous server other than address and port information. If customers are charged based on ingress/egress, it could be affordable for users to run these small programs on a "cloud server" due to the smaller amount of data transfer. With less data being sent to these third party providers, the privacy concerns would arguably be reduced as well (cf. eliminated).

The ability to connect devices directly over a network, including the internet, should not be monopolised like so many other aspects of the computers and the internet today. It should be available for everyone. The only cost should be paying for the globally reachable IP address and a tiny amount of traffic required for running a rendezvous server.

1. The advantage here is that the program can be easier and quicker to compile and users may be more inclined to read the source code and, optionally, make edits and recompile. Non-commercial, not a complex program like a web browser that is prohibitively slow to compile that almost no one compiles for themselves, nor one that few people have both the aptitude and inclination to read, edit and improve its source code.

2. Yes, there can be exceptions. For example, in some cases two clients using the same ISP might not be able to reach other directly. But these cases are the exceptions, not the rule.