The bump comes on posts or comments that have received votes (excluding self votes) that come in under 0.02. Dustsweeper comes along and upvotes to make sure it goes above the dust threshold.
Currently it's running with a limit of 2 upvotes a day as it continues to gather SP (either by delegation or accumulated from curation rewards).
Thanks, for clearing that up. It's such an ingenious service and I hope to one day grow strong enough where I can make an impact delegating my SPs to community supporting programs like this.
It's great, and looking at SteemWorld it appears you've received a couple of dustsweeper votes now as well.
Woohoo, what a coinkidink. It's like hitting the penny slots, haha.