I have played arround with HYIP`s for some time. Here is what I think about em :
In my opinion, there are no HYIP project, that really invest in forex, stocks, or something else. Well, maybe there are projects like that, but the minimum investment should be ( in my opinion ) at least a 100$, not 10 or 15.
So as I think, most HYIP ` s are simple ponzi projects. Projects where money from new clients is used to pay to old client. So it is like gambling, everyone knows, that eventually the HYIP will drop and people will loose money, but the goal for every1 is to catch the profits , or most of the profits untill the drop.
Of course you can make a profit there, if u use smart money management, work out a HYIP picking criterias and so on, but for me something more real came up, maybe I will return to them when I have time .
P.S. I invested about 30$ in different projects, and was in profit at first , with about 67$ for three days, but then I put all of them in one project that already paid me once, and on the next day they stopped making payouts, so here is a first ruel of investing in HYIP`s : Never put all your eggs in one basket. I got a little greedy and made a mistake, it is good that it was only 70$ , not 700 =)