"When should we use the
downvote button?"

Fantastic question. As we all know that the opposite of upvoting is downvoting. There are several reasons why the downvoting power can be use.

1. Unqualified Post : unqualify post simply means post that are not meant to be in this community e.g posting of Porn or erotic related post. This kind of post can be downvoted.

2. Use of wrong ashtag : some posts are not meant for some certain tribes and when such post are seen it can be downvoted. Such as posting sport in weed community when such post does not relate weed.

3. Hate speach the truth is that we are suppose to respect each other opinion. post that is done for the purpose of saying something negative about the community as a whole can be downvoted. For example someone who does not like weed, posting something negative about weed just because the person believe is against weed.

4. Undeserved upvote received: some weeks back i noticed someone post and instantly due to automatic upvote the post got some pob and the person delete such post after earning some pob. @nikkybabe noticed this and call the attention of @onealfa.pob and @leprechaun and the content was downvoted. The truth is that when we see some post earning undeserved reward it should be downvoted.

5. Notice of fraudulence act : Of recent @onealfa.pob downvote some people's post just because he noticed the goal of such people is to get pob and sell. Which has been the reason for downward movement of pob price.