I support @steemcleaners as well, they do a great job both informing and reducing the spam.
Remains to see if @pleasestop manage to up his service to a level of wide acceptance. I think he might, but may be he need some helpers as this probably become too big a task for one man and a bot. The spam he aims to fight is also very much a newcomer situation, where you got few followers and try to get your footprint inside community many look for the easy solution of saying HI by commenting posts and ask for a follow or upvote.

Issues about storage mainly appears because we are decentralized to a degree, and copies of everything is stored in each node.