Leaving a one-word comment that adds nothing to the conversation of the post you left the comment on and then upvoting your worthless comment tells people you are a taker on Steemit and not a giver.
Omg THIS. Yes. I've said it before and I'll say it again, anyone who posts these garbage, spammy comments on my posts will get flagged (at just 1%) for being little shitheads. Granted, I will always explain my reasoning and the fact that it's a mere 1%. Hopefully, this steers some of the newbies into behaving more Steemit-appropriate.
The unfollow rule is a good one as well.
Or you can link this post to their spammy comments. Or post how you feel about it and respond to them with a link to your post. That's why I wrote this post. I got tired of explaining it to people who do this on my blog.