I saw Craig Martelle announce it in the 20booksto50k FB group. I didn't know he was a part owner. Anyway, never used this promo site (just know it's from Mark Dawson) but I heard people say it's great for freebie so I might try it soon. I am a gold member for Written Word Media so I get a discount on every promo I book. It's been well worth the membership and I save a lot of money when I use those sites now. WWM has partnered with a lot of sites lately including Fussy Librarian. They also have this neat new tool where you can book promos easily in just a few steps. I'm anxious to see what the next partner will be.
On the other hand, I stopped using Bookbub since you mentioned it. Haven't used it in probably close to 2 years. It's too much money and not nearly as effective as it used to be IMO.