I don't think we need a common definition, just pick your own definition and if people like it they will trail you. For a long time people have fought about wether we should downvote things or not. Now we can just do it.

before fucking up someone’s day and killing their post or comment. I see this bullshit far to often.

If that post got fucked up and you believe it's actually good content then you should upvote it. That's how proof of brain was supposed to work.