See my related comment. It was a popular idea around 2005-10. As mentioned Red Swoosh was primarily sold as a “p2p” CDN, was bought up by akamai for a billionty dollars, and promptly disappeared. AWS S3 also implemented a torrent interface early on. AFAIK they keep it alive in name at least, but its effectively deadcode with $0 revenue as far back as Ive ever known. A handful of private companies built p2p themselves, but eventually moved off. As an example p2p is where spotify started in this time range and then moved to a CDN (us) for better consistency and not having to deal with it themselves.

The primary business problem is one of visibility and control. The customer UX would be entirely out if your control, and exceedingly variable, based on factors you (the provider) cant even see. At the same time CDNs were pushing down to cents per GB delivered by 2010, and ~1¢/GB by 2015. At a penny per GB distribution for higher throughout, better visibility, and control CDN distribution costs started to not matter compared to other costs and priorities.

Oh! Porn delivery companies, theyre an interesting content distribution case. AFAIK commercial CDNs are still way too expensive to meet their business model needs. My recollection is that they all built their own in house CDNs, like GPs “run a bunch of VMs” approach, or used a peers. This was accelerated as all of those companies consolidated ala MindGeek in the 2010s.