I will be the first to admit, yes, there are several unlicensed and untrustworthy online casinos actively seeking prey on the Internet.  However, in the defense of the multibillion dollar online gambling industry, that is not remotely the status quo for online casinos.  There are more than enough healthy, stable, long standing, and trustworthy online casinos and they are not hard to find.

One thing that the Internet does well is provide a lot of information.  There are more thane enough reviews from both professionals and consumers alike to offer a starting place to figure out the history of service at a particular online casino.  In addition to that, most reputable online casinos offer information on the audits they have done by well known independent companies like PricewaterhouseCoopers. 

Another way of knowing an online casino is a safe place to spend money is by paying attention to their software supplier.  Software companies like Playtech and Microgaming are very influential in the online gaming world.  So much so that they have operation standards for the online casinos they license to use there product.  You can bet that if an online casino is involved in shady dealing a company like Microgaming will pull their product in a flash. They will not risk having their name ruined by being connected to a con site.  

Like with anything else that involves spending money online, always be very careful and look for a level of professionalism.  Online casinos are big on earning trust and the safe ones will almost brag about the clean audits and seals of approval.