Good question. The thing that was news to me is that it's happening on very large blogs, not random sites and that it's being sold to and used by well-known startups. Like you, I expect sockpuppet accounts and random linkbuilding garbage, just not at this scale or with this much distribution.
The thing to note there is that despite being on a "black hat" website, most of those ads are from marketing or SEO companies linking to their own legitimate company websites. It's clear most of them just see this as how internet marketing is done.
I also note that as a not logged in user, the Twitter just shows me "related tweets" from people actually hiring or offering to sell social media content.
Good question. The thing that was news to me is that it's happening on very large blogs, not random sites and that it's being sold to and used by well-known startups. Like you, I expect sockpuppet accounts and random linkbuilding garbage, just not at this scale or with this much distribution.