I received the following message from MSGTAG support; the website is still down. I'm posting so that anyone doing a web search might have more luck than I did figuring out what's wrong:
As you probably know we are having serious problems with our current
server hosting provider. Despite their market reputation we have had
surprisingly long delays in tracing and rectifying an outage that has
affected the server that is responsible for MSGTAG tags and the system
that allows us to email users about the problems, as well as some other
sub-systems. This has meant that the error has not only affected all of
our users and customers, but has also prevented us from getting the word
out.
