Absolutely. As others said, maybe not as much for established...

Absolutely. As others said, maybe not as much for established blue chips, but certainly - to some extent - for more vulnerable small caps.

There are even trading algorithms (bots) that automatically compute sentiment across social media. I'm not saying this is the case with CDY but there definitely is such a thing.

Here is an old article about data mining for the purpose of share trading.

http://fortune.com/2015/12/07/dataminr-hedge-funds-twitter-data/

That's one reason why it is so idiotic to lament about one's own investment on public media. It is neutral at best, and counter-productive at worst.