@rvanstel It's a little risk to keep money on an external exchange. But with full safety settings the risk is maintained to a minimum. I like to divide my money on different exchanges and wallets to mitigate the risk of losing a lot of money. I'm participating in the arbitrage fund from mixcoins.com for over a year now and I'm very content about the product and safety.
RE: 3 ways to get interest on your bitcoins!