Spamming comments is frowned upon by the community.

Comment spam is currently defined by @steemcleaners as:

• 10 or more generic comments per day that are not in response to a question posed by the post or comment. “Thanks”, “Great Post!”, “Informative Post” , “Great Photo!”, “Good”, “Like”, “Nice”, “Wow”, “Cute”, “Follow me”, etc.

• Commenting on old posts to hide self up-votes or a voting trail.

• Copy/Paste comments that serve no purpose or the purpose is self promotion (including copying and pasting similar comments in rotating way).

• Comments that inform the contributor that they have been up upvoted, resteemed, or flagged when the curator does not actually upvote, resteem, or flag the post.

• Fishing/farming votes by using multiple accounts to comment on posts by known comment curators.

• Unsolicited and off topic referral links.

Continued comment spamming may result in action from the cheetah bot.

More Info: Abuse Guide - 2017.