I can answer this one because it was one of my dirtier SEO tricks.

Expired domains and Domains on the marketplace, with hundreds or thousands of “backlinks” to them, are valuable. In the listing you may see something like “20000 back links.” And those links are usually worthless , spam, and will vanish as soon as you buy. But you can find domains that have real backlinks. TEN backlinks from reputable websites are more valuable than a thousand spam BLs.

You used to be able to buy and run software , “backlinks explorer” to investigate everyone who links to a domain you’re thinking about buying. And you can also research a “20000 backlinks” claim to see if this is just someone spamming that domain all over blogger and forums.

A good domain to buy will have legit backlinks from real websites that the website linked on purpose. If it’s been spammed thousands of times for a “5000 backlinks claim” , expect google to punish it!

Because if you 301 them to your site, google et al assume you’re the legitimate successor to that website and people mean to link to you.

So you come up higher in search.

I’ve used this to be the first or second result on google. And certainly on the first page of results.

It overcomes downranking for being a new domain nobody links to.

Google has its own criteria for evaluating whether your page is spam or a scam, and whether you’re abusing this to promote spam or a scam.

I have a trio of ancient highly ranked domains that I forward to a new page for about a year.

They’ll hit page one on google within a week or two or three.

After I remove the 301s or recycle those domains, the pages usually still come up within the first page of results afterwards.

Before you get too horrified here, I did this to bury a “competitor” who had registered a similar domain name, stolen my entire repo and website from a disgruntled employee, copied all my software and copied my webpage word for word trying to drum up business on my IP. The whole time they mocked me in email about stealing my customers and putting me out of business.

It worked. (Sort of. If you hire them they don’t actually have any idea how to do what I do.)

I did not do this to scam or phish or what have you. I just did this to bump them from #1 on google. Which they got by incorporating with a similar business name and registering with a similar URL.

They did ultimately manage to shut that business down and disrupt it after years of this and I moved on because I have other talents and this venture wasn’t profitable enough to deal with this entity kneecapping me for years and years.

But on my way out, I forwarded all of those domains to a reasonable and legitimate website that’s in the same line of work, resulting in them now dominating the other site in search. So I walked away and used this trick one last time to at least ensure someone searching for this subject would end up in some safe and reasonable hands.

What’s my point in sharing this?

It’s that the other website has no idea I did this, and has no control over it. You might see this and assume the worst about the other website.

someone could be doing this to manipulate SEO or search results over sites they don’t even own. For reasons that might (?) make sense or be well intended.

and for reasons that don’t, or might even be malicious.

* MULTIPLE edits for clarification