I agree with the virtual currency part since its about luck, but with Pennystock the more you know how to read graphs -- the more you can predict which stock will do you well. Pennystocks aren't like gambling as people presume it is. Pennystocks usually are easy to navigate through if you understand the market and know what you're doing. It's why I may start soon (I won't use all my money though).
It's actually the exact opposite. Penny stocks are based purely on luck and research, virtual currencies can be invested in by knowing how to read a graph. I was a penny stock trader for about a year and a half when I was younger. I subscribed to every single newsletter and website I could find and spent tons of time researching stocks. Even so, there were days I'd wake up early and buy at market open, and five minutes later the company was worth 50% of what it was previously worth. There were also days where I'd watch it climb to 100% of the value I purchased it at, and I'd sell, then it'd continue climbing to 500%+. Other days I'd not sell at 100% and it'd fall right back to a loss.
Virtual currencies, though very volatile, are actually much more normal financial graphs. You can easily identify trends and patterns in them that would never exist in a penny stock. A good financial trader could make tons of money off of them.
I don't do either anymore. Now I invest in real currencies over the FOREX market. I look at graphs like this all day, and I identify trends (like currently, the short term trend is in jeopardy and is about to either go down or up drastically, my bet is on up) for investment.

So, then I open a trade window:

Volume is set to .2 or $20,000 worth of Yen that I'm purchasing. Hit buy (since I said earlier I thought it was going to go up, otherwise I'd hit sell), then set a point to automatically sell at. I do this thirty times a day, and I've gotten quite good at it, but it's still no magic money maker. There's days I've lost huge amounts of money.