Since I'm not buying stocks myself... Because I would rather invest in commodities rather than in fragile stock markets IMO... I believe in physical commodities rather than commodity shares even...given the financial and political scenario of current time commodity (Gold/Silver/Precious Metals) is the safest investment. Dollar and euro may become toilet papers tomorrow, but gold/silver won't. Do you know that that silver will extinct by 2020? so if you have a quantity of it... You can expect 500-600% return in 5-7 years.
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Ok regarding Facebook shares... As much as I know they will go for issuing IPO, where you can buy it on face value instead of hyped up market price. Then you take the advantage of selling a part of it when the shares will be released for trading in the secondary market. Wait for 3-6 months before selling, the value will hype upto 3-400 % as per most analysts. Then sell it before it falls and settles at around 50-100% higher than the face value... That will be another time for buying, since it will again go high after that but in a stable way...