The world of finance operates thusly:
1) Things operate by established principles,
2) Someone tries to take advantage of that to game the system by inventing some new system,
3) Other people also do that new thing*,
4) This becomes a newly established part of the principles, return to stage (1).
Everyone is trading for what things are worth now? Establish a futures market.
Everyone is trading upon shares going up? Work out how to benefit from them going down.
You have to arrange for your buying and selling to go via a person shouting at other people in the middle of a noisy room? Establish electronic trading.
Trading is communicated rapidly via a copper networking cable? Fibre optic cables!
Fibre optics limited to the speed of light in glass? Line of sight microwave relays...
It is no surprise that someone tried to trick the system by effectively crowdsourcing market-manipulations (a "wetware botnet", you might say). And that opened the floodgates for the (other?) established traders to get in on the act. They were probably thinking about it anyway, but hadn't actually tried it (successfully) until they noticed it.
Two ways it could go, now:
A) Firms like PwC/whatever establish a whole lot more diverse electronic presences in reddits, chans, etc and monitor (perhaps even occasionally participate), ready to react, nudge or even assume/presume authority when something happens. As much as they can currently do within the rules.
B) The rules get changed substantially to prevent such spoiling (but also probably a lot of the newly discovered legitimate dabbling, that can't be discerned from the trolling they're trying to stop).
Either way, it won't be the last. Both further similar 'wild west' economics (the paying/gifting-in-kind of social media Influences is another problem, especially in the helath-and-beauty fields) and whatever The Next Big Thing turns out to be.
* - If it didn't work, the original won't do it for long. If it does, they keep on doing it, get noticed by others, etc.