Within Netflix, things look much the same today as yesterday.  The company hasn’t been hit by site outages, big resignations, or scandals of any sort.  But Facebook’s decision to let users rent The Dark Knight apparently spooked Netflix shareholders to the point they sent its stock tumbling 5.76 percent.

That’s of course a big, nasty drop.  Then, making matters even worse for Netflix fans, there’s the fact that the Nasdaq rose 0.73 percent today, meaning Netflix’s fall occurred despite a market-wide semi-rally.

That might say a lot about how much faith shareholders have in Netflix – and/or how much they fear Facebook.

Consider that Netflix ended 2010 with 20 million subscribers.  Facebook hasn’t bothered to update its official user count since July, and at that time, the social network had 500 million users.  With that many people behind it, Facebook has the potential to disrupt just about anything.

Or, if you’re interested in another reason for the dive, there’s the simple “surprise!” factor.  Goldman Sachs analyst Ingrid Chung acknowledged according to The Hollywood Reporter, “Facebook represents a new potential entrant that few in the investment community were concerned with prior to this announcement, so we believe it does indeed represent an incremental negative for Netflix shares.”

Good luck to (remaining) Netflix shareholders when the market opens again tomorrow.