
If a manual penalty from Google has been applied, you will get to know
about it from your Google Webmaster Tools dashboard. Often times, the
report will tell you what backlinks to your site have caused the action,
in which case you can go right ahead and disavow those links
immediately.
Or rather, read the following article before doing such a thing.
Pre-emptive disavow
What about when there's no explicit manual penalty, and you just need to
keep on the safe side of things? Sometimes, it's a good idea to
pre-emptively disavow certain links (again, take care while doing this,
and read this article to avoid common disavow mistakes
that people make).
that people make).
Often times, people will do bad SEO that they're not proud of. They may
even hire an SEO who would 'promise results', but would use some of the
bad practices to make the website perform well. Such boosts are mostly
temporary, and when the bubble bursts and you realize what's really
going on, it's too late. BAM - You're under penalty. That's the perfect
situation to use the disavow tool to discredit bad links to your site
from a certain period of time.
If there's no manual manual penalty, but you're still worried that
someone might be doing - or trying to do - negative SEO, or you come
across a spam bot that's pulling up a bunch of links to your site and
you have no idea where it came from, then that's a perfect time to
pre-emptively disavow certain links. So the use of the Link Disavow Tool
isn't always warranted by a message in your Google Webmaster Tools
dashboard.
If you have done the work to keep an active look on your backlinks, and
you see something strange going on, don't just wait around! Feel free to
go ahead and use disavows, even on a domain level, especially if
there's a spam bot involved, and you have no idea what it's doing, and
why.
Also, if you see links from domains that don't relate to yours, you
should probably check out what's on before Google does. So keeping a
constant and vigilant eye on your site's backlinks is really important.
You don't want to be caught up in a penalty 'out of the blue', which
could cost you valuable time and effort. All the best :)