While I never tried to join their community proper, several years ago I did send them $36 to get a lifetime "ARPA" membership. The service is, as you might expect, old fashioned: you get a grand total of 600MB of storage and access to a regular user account on their NetBSD servers. Meanwhile, for a few dollars per month from umpteen VPS providers I can get tons of storage and the ability to virtualize just about any operating system - and like many, I don't expect to get to a financial state where that would be a significant burden anytime soon, hopefully ever. But dealing with billing requires some level of active maintenance, however small, and in the long run providers come and go. SDF requires zero - I can have paid zero attention to the service for years, but if I suddenly need to do SSH forwarding to get past a firewall and don't have anything else handy, the shell is a few keystrokes away; if someone chances upon an old link to some basic web content I set up on it years ago, it will work. They've been around for close to three decades, and as a small enthusiasts' group (which survives despite having long had very uncompetitive prices for their higher-level services, which unlike ARPA have periodic fees), they're not as vulnerable as your average big company to going out of business when industry trends change. Personally, I'd have paid a lot more than $36 for that quality of guarantee!