Follow buttons and the logged out user
blog.superfeedr.com
blog.superfeedr.com
What? No. That's ridiculous. For as long as people have used the phrase "logged in" there have been logged out users. A simple Google search for the phrase turns up a thread† from 8 years ago, and that's certainly not the first either. Coined the term? Really?
† http://www.unix.com/unix-advanced-expert-users/25178-who-9-c...
It deeply unsettles me when I see a button for which this tactic doesn't work. Rationally, I know there's no difference; you could have an href="example.com" and just capture clicks to do whatever you want. Nevertheless, it still spooked me enough to stop me from clicking the button.
Given the nature of self-updating browsers and devices being permanently with or around users, I suggest something else.
Let me follow whoever I want without creating an account, store these preferences in localStorage, then use it to build a news feed on the home page, just like a logged in user.
Then, unobtrusively suggest other features that can only be made available to signed up users, due to technical constraints.
(No, notifications are not such features; a browser extension that checks localStorage and raises browser notifications a la Chrome should be enough for non-logged in users).