Will removing the incentive, which is the upvotes, help reduce this spam? You can disable public access to the points gained by a new account (or may be for every account).
Or if the ranking that's attractive to spammer, may be try experimenting with randomizing order of comments in a discussion.
What I hope not to see is the Reddit method of "Oh you made a new account? Cool. You can't post anywhere and you can't post until you've posted catch 22"
Or if the ranking that's attractive to spammer, may be try experimenting with randomizing order of comments in a discussion.