When I first started exploring Bitcoins I saw adverts on a load of sites about a shared mining pool where you pay a small amount of btc and this helps to pay for their mining equipment and they then give you back your money with a percentage bonus a week or so later. Ok, sounded too good to be true - and it was - but at the time it was being advertised heavily, sounded legit with a well-presented website, and lots of other people were investing in it. Luckily, I only lost 0.1 btc, but I'm sure others lost a lot more.
All I'm saying is that the pro of Bitcoins is their anonymity, but it is also a negative - its easy for somebody to present a believable business model, grab a load of coins, and then vanish. Probably better to mine yourself, although you need a stack of cash to buy the equipment!