Around an hour or so ago, SFF went into read-only mode. Apparently, it wasn't the only one - Stack Overflow and Super User went down as well, and I assume that all 153 sites experienced the same.
There was no warning on stackstatus.net, and @StackStatus didn't post anything. What was the downtime for?
As @CreationEdge said...:
People are mostly poking fun here, but it could be a teaching moment to explain why the site goes down for small periods of time every now and then, when not "scheduled" (to our knowledge). Not every user is going to understand the dynamics of how a major website functions.