Yesterday I got a generic error on the desktop that Anti-Splog could not connect to the server. (Or something like that.) I figured it was a maintenance/upgrade thing and I ignored the warning.
Today I see yellow band in the desktop that reads: "Anti-Splog is almost ready. You must enter your WPMU DEV Premium API key for it to work."
Sure enough, the API key field was blank. I grabbed the key and plugged it back in and all appears fine. I don't think I made any updates or changes to the site yesterday or today.