The thing is wall street speculation is now highly automated. ... and cause a sell-off run much more efficiently than humans reading twitter ever could.
This is exactly what triggered it. The page was up for forty five seconds. 45 seconds is not enough for humans to read and understand it, but that is plenty of time for bots.
During that 45 seconds, assorted stock-trading bots picked up on it, scanned it, and sold over 3M units, or $153M, of their stock. That's over 30x their normal trading levels.
The huge uptick in stock sales triggered another bunch of automated trades, and over the next 18 minutes they had more trades than they had seen all quarter -- the last trade spike that big was after their last earnings report, when the price jumped from about $37/share to around $50/share.
Then, about 18 minutes after the brief posting, trading stopped because of the anomaly. It is normally an effective tactic when trading bots go crazy.
20 minutes later trading was resumed for the remaining half hour of the day. There were over two million trades per minute over that half hour, and the stock price continued dropping from $51.24 to $42.27, with a slow but steady drop today down to $38.49. Days like this make me laugh at stupid investors. No point in selling now, the value is already lost. It is unlikely another bombshell will be dropped. Selling just reinforces your losses.
Of course, if you're a long term investor you'll note that nothing about the company changed; no deals were cancelled and they are still growing in ways that matter. Their stock is low, making it a good value to pick up.