Where do services like serpstat.com (former prodvigator), ahrefs, semrush, advs, spyfu, spywords get statistics?

Question

contextual advertising

1. Statistics on backlinks to the site. Do they really have their own crawler on the Internet?
2. Statistics of keywords, frequency of queries per month.
3. Search hints. It can be parsed. But maybe you know other options?
4. Issuance of advertisements upon request. Emulate entry under the ip of the desired region and parse?
5. Cost per click in Google and Yandex.
6. Others, if you know, but not listed in this question :).
Thank you all in advance.

Answer 1

1. Statistics on backlinks to the site. Do they really have their own crawler on the Internet?

Yes climbs, still exchange information with others
Wordstat is parsed by all sorts of plug-ins for browsers, Indians drive captcha
It's easiest to rip them off
Yes, and plugins, and they do not work correctly, information is often given a curve, unreliable. Then I check, I don’t have ads, I look at them - I ask support from where? They send a screenshot like they have advertising. And I heard a lot of such inconsistencies.
API yadex-direct requests you make and that's it

Answer 2

4. Issuance of advertisements upon request. Emulate entry under the ip of the desired region and parse?
Yes, plugins. Probably through different VPNs. Therefore, statistics on the number of requests for specific keywords in Yandex and Google are not accurate. Because similar parsers, position measurement services generate these empty requests.