Having ads on the site doesn't necessarily mean they're bringing in revenue. Most of the ads on my own site here are my own and, therefore aren't generating any advertiser revenue. In fact, I've only sold a total of $9 worth of ads since I started this site...lol
It does seem a bit odd that they want to invest money into forex to pay their members. I'd worry about that. Mostly because forex is a risky venture, but also because they want you to spend more money just to get what you already earned. That doesn't really seem fair to me.
Do let me know how it turns out!