What is the sense of these websites with random content?

Most sites like these fall into 3 buckets:

- Serve ads. Many of us won’t see the ads thanks to content blockers.

- Publicize links, as often for affiliate link spam (generate unintentional clicks) as for SEO (backlinks). The first site you pasted has CPC affiliate links in the footer. Sometimes this is hidden in a CMS plug-in, so the site operator doesn’t know that their site is serving pages that aren’t related to their site.

- Phish credit cards or passwords. If a scammy site has a shopping cart, it’s probably doing this. This is usually on hacked servers, while the first two are often just on low-end hosting services.

Once upon a time there was a guy who called himself "Eli" who wrote a blog post called "SEO Empire" which proposed that a person who was serious about SEO wouldn't need to go begging for links or even creating content that attracts links, but rather they could create a vast pyramid of sites that would generate PageRank out of thin air.

Such a person would make a vast number of low-quality sites that make hyperlinks to medium-quality sites that in turn would make hyperlinks to high-quality sites.

I could say the idea captivated me completely for a while. I couldn't think about work when I was at work because my mind was filled with thoughts about that sort of thing.

Unfortunately Eli's post is no longer on the web. He still has a "Blue Hat SEO" site but like too many other sites today his SSL configuration is broken. He got in a lot of trouble after he posted a neural network written in PHP that could crack CAPTCHAs. That attracted attention from Russian Hackers, the FBI, and a person who couldn't tell the difference between anime and reality.

Sounds vaguely like this PHP malware:

https://github.com/bediger4000/php-malware-analysis/tree/mas...

https://github.com/bediger4000/php-malware-analysis/tree/mas...

But only vaguely. I would guess the random content is for human consumption, and the underlying PHP redirects bots to some other SEO thing, which is opposite of the malware I linked to above. But that's just a guess.

A lot of malware is so poorly coded it's impossible to tell what the intent is. Your random content could be a result of that, too.

Ad spam. Motive is monetary gain nothing else.

I know a guy that used to make sites like this. The gibberish you see is scraped from somewhere and its purpose on the site is to give Google bot something to see and rank the site for search terms related to the content. There's a PHP script running behind the scenes and when users from a certain geographic location or meeting some other criteria happen on the site by clicking on it from an organic link in Google search, the content is switched out for a page full of affiliate ads linking to eBay, Amazon, or whomever.

The "thin" sites with this stuff are generated by a script and the spammer will create thousands of them on cheap hosting. The economics work since it usually takes Google a few months to boot the sites from organic search but by then the affiliate money has been made that more than covers the cost. And the whole time Google is pulling the sites off their search page, more sites are steadily being generated.