Going into a bit more detail on this.
Me and my partner are in a few niches that get absolutely clustered with dirty SEO's. There's essentially no ethics in these niches and we've been in the niche for years now (since 2013). Over the years I've seen first hand just how much negative SEO can affect a site so I'm not just talking out of thin air. We've carried out tests, strategies and even had to take out a few sites ourself (I don't condone negative SEO but when you're in a very short term churn/burn niche that is full of dirty players, you gotta do what you gotta do).
First things first - negative SEO doesn't just mean buildng shitty links to a competitors site in the hopes that they'll tank. Sure, links are one of the many factors that come into play - but to say links are the only way to bring down a competitors site is not true. As I said previously, I don't want to go into the details but there are at least a solid 5+ methods of harming someones site, providing the site isn't too established obviously. If you're an authority in the niche, you pretty much have a shield around your site so no amount of neg SEO will bring you down (from experience).
I have several clients in very high competition niches (think 1m+ monthly search volumes). These are massive authority sites that outrank Wikipedia and many other big sites for generic, highly searched keywords. Since I handle the SEO for these sites, I see on a daily basis just how much effort others go through to try harm the rankings. I've seen it all. Not just the typical shitty links, toxic anchors, trying to over-optimize a keyword.. but actual, unknown neg SEO strategies that you don't see being shared around on forums. There's a reason why you don't see these methods being shared around; because they work - in certain circumstances. I'm fortunate enough to have big clients across a wide variety of niches so I've seen all sorts of neg SEO attempts. This has allowed me to copy the same attempts and repeat it on our churn/burn niches and the results.. well, let's just say neg SEO still works if you do it correctly. I'm not going to share these methods but we've been able to take out competitor sites in a few days (completely deindex them) and it was a "piece of cake". Success rate is also pretty high but the target site has to fit a certain criteria. You won't be able to take down an authority site no matter what you do since Google will have already established them as an authority in the niche - so like I said they have an extra layer of protection around the site.
For example, one of my client's site ranks for approx 450,000 keywords (has over 20,000 #1 rankings for BIG MONEY keywords). It's no doubt an authority in the niche. The anchor profile is so messed up - receives hundreds to thousands of spammy links, toxic anchor links and more on a daily basis. Does it affect the site in a negative way? No. Like others have said in the thread, once you're an authority - doesn't matter what scale you build your shitty links or try to mess up the anchor profile - the extra layer of protection will block all these attempts.
The issue is most people nowadays consider neg SEO to be:
- building shitty links to a website
- trying to over optimize/screw up competitors anchor profile
- building shitty links with toxic anchors
- building quality links but using toxic anchors
These methods worked years ago. Google have caught up to these methods and they've essentially devalued them (to an extent) as others have correctly said on this thread.
But that's not to say negative SEO doesn't still exist.
Back to my main point, negative SEO works very well in 2018. In our tests, we were able to completely deindex sites in a few days using a few of the methods we've discovered. Can we deindex/harm all sites with a 100% success rate? Of course not.. no one can. But over time we've managed to use the data and experience we have in order to create a "minimum threshold" and we now have an approximate "calculator" which gives us a good idea whether or not a site can be tanked using the methods we've discovered. Again, there's a reason why these methods aren't widely available on forums, etc - because anyone who knows them will never share them. I'm sure there's a few members on BHW who know of these methods and you'll know exactly what I'm talking about.
The thing is a lot of the really experienced and skilled SEO's aren't on the forums. I know guys who are spending high $XX,XXX/m just for their neg SEO operations. It's ridiculous when you see just how much effort and time some people put into neg SEO and that's because it works. Again, I'm not talking about the typical "build shitty links" or "over-optimize anchors". I'm referring to working, unknown methods that are extremely unethical and requires $$$$ to execute.
In my opinion, negative SEO will always continue to work. Yes, Google are getting smarter and can now devalue links and so on.. but as long as we can game the algorithm for our ranking benefits, we can also game it to take down rankings/sites.