Useless, dumb and self-promoting comments, call them what you want but they only spread selfishness and shallowness. (a very quick rant)
Who even makes these?
Steemit is a great place to earn by posting, commenting and also curating.
It's a pretty new concept and it allows many people to create new content while getting paid.
Cool, right?
Unfortunately, these people only understood the earn money part, and they completely forgot to create and make new content.
Where can I find these comments?
You can find them everywhere! new, or trending posts, there's always that one word comment that is desperately looking for a spare upvote, as if 0.001 cents would make a difference in the long run.
They may be disguised as friendly comments but they don't really add anything to the conversation!
How they affect the community?
It's flattering to see that, after spending a considerable amount of time writing a post, the only comments you (or other posters) get are "wow amazing, check out my new post!" or "upvoted and followed ;)"
Please don't make a fool out of yourself, if you don't have anything to say, don't comment.
Tl;dr: comment whatever you want, but stop the shallow self-promotion
you have to give to receive, and Steemit is no exception
rant/off