There are lots of early stage startups these days that, on the surface, are easily replicated. The fact is though that they were the ones to do it first/successfully. This isn't to say that someone else can't come and eat their lunch, but as an investor, if you think the market in general has potential, you obviously have to bet on the best horse before the opportunity gets snapped up. Fraud is always going to be an issue with companies that deal with transactions but money can help alleviate to put the systems in place to deal with it.
