Hard to say. The instability is largely caused by DDoS attacks on the service. The strength and frequency correlates almost directly with the market cap of Steem. Though that is just my baseless guess. There are nearly a thousand channels on steemit.chat with, I presume, their own micro ecosystem of poltics and tech savvy folks.
It's an arms race that will never be won or lost.
Anytime you offer a service that's popular there's going to be either competitors or just assholes hammering the server. Unfortunately except for mitigating these there's nothing anyone can do except put in controls.
Downvoting a post can decrease pending rewards and make it less visible. Common reasons:
Submit