Hello Rikafip,
I think that
[ANN] Workbit - Freelance platform belong to be in the list of using bumping service.
Topic is self-moderated, lots of old Newbie and Jr.Member accounts that started to post on January 4-5. They post only in this exact topic and create a conversation between each other. I've made a simple post with hint that might help project to improve, but it seems on purpose it was either ignored or got no reaction.
You are absolutely right, they indeed hired bumping service and by the looks of it, they hired most popular one, Vitor Services. All accounts are at least few years, some are even from 2011 (I still wonder how they have so many accounts from that early bitcointalk period) and they are currently active only in Workbit announcement thread. Standard Vitor Services M.O..
The ANN thread owner did do bumping services but it not mostly done by the Vitor Services cause some project owner do it by themselves, I an saying this cause I have seen a lot of fiveer users who offers services in selling forum account which I think they can easily buy and pump the ANN themselves, either way, it could the work of Vito but they are not always behind it.