Facebook’s post-IPO existence has been totally unpredictable, and beginning Thursday, it will face one of the roughest times ever for a freshly traded company, and that being the very first day that some insiders will be legally allowed to dump the stock. With quite a few initial public offerings, Facebook’s May 18 debut included a “lock-up” agreement requiring shareholders to hold on to their stock for a certain period of time. Insiders will be allowed to sell of approximately 271 million shares on Thursday. Since its initial IPO, Facebook has lost nearly 1/2 of its value since its debut, so much so, that many are predicted to dump the stock.