Things You Need To Know About Negative SEO
When we look at positive SEO in broader perspective, it is mainly a process to positively impact the ranking of a URL. It is usually done with the help of manipulation of variables in the links, content and/or other user signal areas.

Negative SEO, on the other hand, is a process which impacts the ranking of a URL in negative manner.

Now, Google tells that there is no such thing like negative SEO. But this statement is not entirely true. When you change a variable within your site accidently, there is a chance for the negative impact to come onto the ranking of your site. Now, if this change of signals within a website can impact the ranking, same effect can be generated by manipulating foreign ranking signals.

Google has been working over the years to prevent damage, due to tempering of foreign ranking signals, from coming onto the websites. But the fact is that it has not been possible to avoid damage entirely. Here is what Google has to say in this regard:

Google works hard to prevent other webmasters from being able to harm your ranking or have your site removed from our index. If you’re concerned about another site linking to yours, we suggest contacting the webmaster of the site in question. Google aggregates and organizes information published on the web; we don’t control the content of these pages.

Reading this statement, it can be seen that Google partly admits the possibility of troublemakers succeeding in doing the damage.
Is negative SEO black hat?
You may wonder if negative SEO is black hat. If we look at Google’s terms of service, most of the negative SEO techniques would seem working on black hat tasks. Now, if Google’s TOS suggest against buying links, any white hat practitioner wouldn’t go for the technique. On the other hand, a black hat practitioner would look into matter whether or not buying links is effective.

Now, it is worth mentioning here that some of the negative SEO tactics are not necessarily black hat. For instance, you may request a webmaster to change the links to an asset, which your competitors would refer to, in order to make replace their links with yours. In this scenario, you are basically trying to negatively impact your competitors’ rankings while improving yours. This way of negative SEO is not forbidden.

Here, it is also worth mentioning that there are several white hat SEO practices which convert into black hat at a specific scale. And there are also some black hat tactics which have now emerged as white hat recently, e.g. cloaking.

Summing up all, it is not possible to term this practice entirely as negative. It’s actually the ways you do this type of SEO. If you are hacking someone’s website in order to sink it down to lower ranks, you are not doing something legal. But the method of winning competition mentioned above is surely something you can do.