Sometimes they just go down, much like this site does. I wouldn't start panicking just yet but people need to learn from the gox fiasco because it's only a matter of time before another one dissapears.
I assume it will be a large Chinese exchange that is giving interest on BTC, that just scream GET OUT NOW more than anything. I don't play those games with my coin and neither do I want my exchange to.
I have some coins (frozen and cash) in this chinese exchange, I make the mystake to use, without take prior some information, and now, yes, I can also tell: Don't left your coins in a wallet! (I decide to deposit when I don't have any idea about exchange and scammers...)
Trusted or not trusted, 2FA or not 2FA, there was to many scam attempts in this field and it's crazy take money in this service.
About btc-e, for what I have understand, they are in a good position and with coin exchange they can continue to survive, they get good fees exchange, so far to going well and not attempt frauds.