Yes, a lot of people are asking about this today.
It is very important to cast all 30 votes for the witnesses who support the Steem community for maximum effect.
I am going to link to my comment which I wrote to someone who asked the same question.
https://steempeak.com/hive-153349/@creativetruth/re-meerwaseem-q6mror
I already give some votes to the witnesses which I like :)
So, the witnesses is menage the code, way of transactions on Steem, and entire blockchaine...?
Each transaction on witnesses side is rewarded, right?
More transaction, more rewards will get witness?
20 independent witnesses which make Steem blockchain decentralized was get compromised by one person?
Finally, last days, specially last 48 hours, some guy, was take over the Steem blockchain by setting up 20 his own witnesses and manage to give them top vote position...
I think that is close enough understanding. Let's all hope this never happens again.