It's unclear whether this can be changed later, and I'm not yet sure whether I want to use my real identity or a throwaway.
After creating an account with the default ¿randomly? generated name, I tried to use an invite obtained from http://198.211.122.115/invited which was linked from https://github.com/staltz/easy-ssb-pub.
All I got back was "An error occured (sic) while attempting to redeem invite. could not connect to sbot"
It worked with http://pub.locksmithdon.net/ though I feel a bit odd trusting a "locksmith" I've never heard of to stream lots of data to my harddrive...
It's cool that anyone can host a pub – basically, an instance of FB/Twitter/Gmail, it seems – but things 1) will get expensive for them, and it's unclear how they'll fund that – and 2) now I have to trust random people on the internet – not only to be nice, but also secure.
As a "random technically aware netizen", I honestly trust fooplesoft more, since they have a multi-billion-dollar reputation to protect. (Not that I trust fooplesoft).