My hosting provider sent along the following message:
We have experienced a DDOS attack today January 4th, which resulted in latency across the entire network. During this time your domain, email, ftp and other services may have appeared to be offline, or intermittent. Our techs have been working as quickly as possible to block the attack and get the network back up to speed.
I was relieved to know that the unexpected downtime was the result of something I’d done. The problem, and I can feel for my hosting provider here, is that DDOS attacks aren’t so easy to block (while also leaving the network open enough to be usable), so I wouldn’t be surprised if performance here is rather variable for a while.