Nitro, stop spreading stupid rumors. The MS has been up and running since the day after April Fools.
Reasons why you might not be able to get joiners when advertising on the server:
1. Ports aren't forwarded properly (People can see the server on the list OUTSIDE the game, not in the game, nobody can join at all. Only exists with firewalls/routers)
2. You are banned from the MS (Do NOT say you weren't banned, the banned list gets updated on an irregular basis. You may have, however, been caught in a range of IPs by accident)
3. Your master server address isn't properly set (May happen accidentally, Server Settings in-game)
4. You forgot to turn on advertising.
5. You are using a version unsupported/banned by the MS (citation needed)
6. You aren't connected to the internet (D'OH)
7. Firewall is blocking srb2.
There are likely many more reasons, here is just a small list of them.