An administrative announcement.
Q: What's this "Federation thing?"
A: A bunch of communities, on different servers, sharing /some/ but not necessarily /all/ of their traffic. Or, in some cases, none. It depends.
The User Guide has a good section:
Q: Does Federation -- different sites and even networks interconnecting -- mean that there might be the same username in different places?
A: Yes. It's a lot like email in that regard. "rosa.martinez" might exist on, say, Gmail, Hotmail, and Yahoo, but be three separate people. Or two the same and one different. You've got to check.
@hanung665 Wikipedia's Criteria of Truth page lists various tests, some better than others.
"[T[here seem to be only three functional, effective tests of truth[:] correspondence, coherence and pragmatic."
"Pragmatic" is "is the knowledge useful in application?"
"Correspondence" is "does the knowledge correspond with that it describes?"
"Coherence" is "are all pertinent facts arranged in a consistent and cohesive fashion as an integrated whole?"
Generalistic and moderated instance.