What methods They used to spammed google ?

Hello everyone, does anyone know what kind of methods they use to spam google with hundred thousand keywords ?

so currently they are dominating google rank at niche gambling in Indonesia with these methods to spam with auto generate contents and subdomain for all keywords.

here the example of the website they used :

https://shubh.io/sitemap.xml

Bad badlink service, microworkers etc..

Without going into deep - they are definitly spamming whitelabeled subdomains
The idea is simple:
Even if nothing gets indexed, the homepage usaly gets. Each subdomain is an own property for search engines, so they're very likly to index the subdomain. And since you handle very niche topics on the homepage of every subdomain, they have a low chance to outrank other pages, at least for a while. And it's unlikly that subdomains will be hit as strong by an automatic penalty as subpages are, so the risk is a bit more distributed.
I guess, with 500k subdomains indexed, we talk about perhaps some million of subdomains.

Edit:
Okay, this is interesting indeed:
Google does not rank it by the content, only by structured data and/or h*-tags. The normal content does not even change. But they're spamming all reasonable schema.org datasets, if you uncloak em.

not a very sustainable way of ranking looks like..

charla said:

not a very sustainable way of ranking looks like..

Click to expand...

Doesn't matter - you can throw out thousends like these, if you have a system able carrying it. If one domain makes $10 and you pay $1 for a domain, you got 900% margin. In this case, we'll talk about way more return, but these are random unicorns.
Add about $500 for server costs and it's profitable fast and can produce a large sum in a very short time. You will still have to adept the system over and over again

This is kind of a spamdexing method. It has been recently discussed in another thread. Basically they have thousands of domains and subdomains. Then all of them interlink and then they create links from these sites to their money site.