Eugene Fama won the Nobel prize in economics this year partly for his work showing that investors can't beat the market. This is particularly true of retail (i.e. amateur) investors. And it's particularly, particularly true of retail investors during splashy IPOs of hugely popular, but reliably unprofitable, companies, whose economic future is utterly uncertain. After all, the only reason to buy a stock is if you think it's not priced properly, which implies that you know more than everybody else. But what, exactly, could you possibly know about Twitter that other people don't?
Still, if you insist on thinking about buying Twitter stock today, tomorrow, or the day after that, we have the flowchart for you.