It s not that simple : How can you know if cex.io, zeushash or btc-e ... Are ponzi schemes or not ?
You don't. All you can see is that some groups have better reputations than others. A service which have been standing for many decades and has a transparent profitable means of using that reputation is far less likely to be a Ponzi than a two-month-old service which has attracted huge amounts of money on the promise of high interest payments.
For example, I'd suggest that:
bitkonan.com is more likely to be running a Bitcoin Ponzi than coinmate.io
coinmate.io is more likely to be running a Bitcoin Ponzi than bitstamp.net
bitstamp.net is more likely to be running a Bitcoin Ponzi than goldmoney.com
I might limit myself to 200 mills (200 millibitcoins = 0.2 BTC) on bitkonan at any one time to try out their site but I could comfortably put 40 BTC in the hands of goldmoney.com.
There are many other factors which can help a person decide the likelihood of losing money through fraud at an exchange:
- Transparency;
- Clear, potentially profitable long-term strategy;
- Contact information for the owners;
- Insurance (where the insurance company is likely independent of the exchange and itself has a far better reputation);
- Endorsements by highly respected members of the community;
- Approval of specialised reputable services which attempt to evaluate the trustworthiness of exchanges.
In this context: regulation is roughly just approval by the government, an admittedly large and long-standing entity but still capable of error or foul play. It does not make it certain that the regulated exchange is not a Ponzi, just far less likely. There is no magic pill; there's risk in everything. Indeed, there are many here that would argue that various governments are themselves running Ponzis.
I don't support it but I certainly admit that government regulation can do a lot to boost the reputation of a small Bitcoin exchange in the eyes of many. What I don't see is why those that want government regulated exchanges also want ALL exchanges to be forced to comply with government regulations. Why can't the regulations be optional? Why can't the government maintain a list of the exchanges it regulates and approves for those that value government regulation to reference? Why should I be denied the freedom to risk my money with an unregulated exchange when I can only hurt myself? I guess this falls in with the "gambling should be illegal" idea but I can't be sure.
Finally, be wary that government regulation is often advertised as keeping the exchanges in order and protecting the investors but often it comes bundled with a whole load of anti-money laundering and know-your-customer regulations which certainly work against the interests of the customer.