This is what I saw, especially for forums about an out of production car. The forums started as very user/community focused, but then all got bought out (I never saw VerticalScope back then, I think it was Auto-something). The new ownership implements advertiser friendly policies and tons of new ads because they didn’t give a shit about the community, this was an investment, and at the same time premium memberships to hide said new ads. This starts to drive away older members, especially those who have moved on to another car, but still enjoyed talking on the forums. They constantly raised the rates for supporting vendors, which quickly drove away small vendors. Some smaller vendors made almost zero profit, they just helped put together some niche thing to help others, but you couldn’t sell your products without being a sponsor. And as time went on falling prices = falling quality of new members who didn’t spend as much, which made it hard for even large supporting vendors to keep paying the high rates. A lot of vendors provided support for the community, and after being priced out of being a supporting vendor their engagement diminished.