what is protection from "pump and dump" here? He isn't allowed to dump the stock for some time? doesn't seem so. One reason Buffet, for example, has special reporting arrangement with SEC is to prevent such volatility, and as a side effect i think it also decreases potential for such pump and dump on his side (not that i imply that Buffet would succumb to such temptation :)

edit: after refreshing myself on Buffet's exception, it seems it protects his interests from volatility, not public's :).

It's required by law to disclose such acquisitions, he just announced it on twitter instead of on a press release.

Also, where is the buy message? A tweet like that is so far from pump and dump...

Watch this for an example of what pump and dump really is... http://www.youtube.com/watch?v=2YbvozZk9Sw

I don't think there's any real protection against someone using entirely truthful, open, public methods to raise the price of a stock.

That's quite a nice scheme for free money, if you are that sort of person: "Hey dude, our share price could do with a kick, fancy a tweet or two? I'll give you 1% of the rallied price." That'd be 170 million dollars for two tweets, I bet not even the likes of Icahn would sneeze at that sort of petty cash. Obviously the money moves from Bahamas to Bermuda and the SEC is none the wiser.

Internet-enabled finance is terrifying.

Yeah but it'd have been much slower and riskier: the combo of instant broadcasting and instant money-transfer abroad hugely amplifies rewards.

This could have happened pre-internet through press. It'd a bit more more difficult logistically but this has always been possible.

There is something very, very wrong with the world.