I am not sure that this is good news. We need strong exchanges, well capitalized and with proven security practices.
If a new exchange gets hacked, it could lead to "Bitcoin is unsafe" warnings yet again.
Bitcoin as a whole is growing. Exchanges popping up is just one aspect of it. Entirely, there are plenty of services and other crypto oriented organizations looking to benefit from the increased popularity of Bitcoin and everything around it. Sure, it may lead to exchanges and other services going down for whatever reason, but it's something we can't avoid. Basically every current exchange can turn into another MtGox at any moment. It just requires the operators to go nuts and walk out with potentially hundreds of millions in funds. I wouldn't worry that much about new exchanges.