The banks who helped boost the price around the IPO are reclaiming their capital gradually, letting stories like this happen, and letting Facebook plan out the next phase of its capital generation strategy. Giving early investors a strong exit was part of the plan.
The biggest irony is that spectators view the downward trend in share price as evidence that the early price was hype driven. In reality, both upward and downward trends are equally impacted by hype.
I plan to invest when the price gets to $15. The only alarming sign so far is the massive number of ads for Target that appear daily on the mobile version. Clearly a few large companies made big ad purchases, and Facebook now regurgitates the news that a friend liked Target again and again at every opportunity. It's supremely annoying and might actually make me stop using Facebook.