I guess it's because MvM indeed, and also because of the 'retrieving server info' thingy that takes a long time (15+ minutes, I've heard) for some people all of sudden. Besides, !credits and all don't work, but I doubt that's an issue.
Not to try and sound like a sheep... but... MvM nlspeed is that problem still happening? I know I had to restart 7 to resolve it the other day, but wasn't aware this was still happening. If it is, that would also explain the decline.
I had that problem the other day and tried to connect to #4 just to check if it's server-dependant, but it occurred then as well.
Well, me, Harvey, and a load of others (at least four people contacted me over Steam about it) had that problem - but I think for me the problem has become less and less anyway (as in, first it didn't work at all, then after +/- 3 restarts, then after 1...). So, while I can see whether I can normally join when I get back to my PC, that won't say that much. I'll ask around on my friends list to see if the problem has been fixed though.
As I said, try now. If it's still happening after this point, I'll have a look to see what could be going wrong.
Ok, respawn timers have been fixed (/ removed), !credits works, admin panel works, DarkiSock does (I didn't test that, but look at the shoutbox; someone from #7 said something) the only thing that doesn't work is !servers. Judging by what some of my friends said, the 'retrieving server info' bug (or however you'd call it) has been fixed as well. It was for me anyway.
It may be replaced at some point, if I can find/make an integration with sourcebans so we don't need to maintain a list of servers in about 5 places.