As I've mentioned before, the comment upvoting works in many different ways, aside from encouraging the sharer to continue sharing, there's now also a "prize pool" that anyone else can participate in when a vote lands on the comments. Say for instance you give it a 10 hive vote, now people can share the same post, depending on the performance of their tweet those 10 hive will be distributed among everyone that shared the same post and paid out after 7 days. So it's both as an incentive and promotion, it also encourages authors to hold HP to give the comments a vote to encourage more users to share their content which leads to more readers, some from hive some hopefully outside of hive.
As to how to determine the criteria, you just gotta check the twitter history of the user and hive, if you suspect foul play in the form of not genuine twitter performance (bot likes, retweets, cashrain, trading/spamming of likes/retweets) we have an abuse channel in our discord where these could be put forward and we then ban the users from earning posh/hive so the upvoted comments would then instead go to the DHF @hive.fund rather than to the potential abusers, but rest to those who aren't banned.
So let's make it happen!