Google's John Mueller said on yesterday's Google hangout at around the 8:17 mark on YouTube that Google is pretty good at ignoring link cruft. Basically old, spammy and irrelevant links accrued by the site over the years.
This is similar messaging from before but the word "cruft" is newish, I think so I covered it again. :)
John was asked:
I checked our inbound links and found there to be lots of spammy links which I added to our disavow file. I wonder how important it is for ranking to keep on top of this. I heard Google ignores them anyway.
John answered:
So in general you don't need to keep on top of this.It's something where pretty much any website if you look at the inbound links will will have a bunch of links that are just kind of spammy or irrelevant. And that's perfectly fine. We were pretty good at ignoring a lot of the kind of cruft that web sites collect over the years. I wouldn't focus on this.
If it's something where you know that previously you went out and bought links. So you had an SEO do something really weird with regards to links, then that would make sense to clean up. But if you're not aware of anything and things are otherwise kind of okay then I wouldn't worry about this.
So again, nothing new with the overall messaging but the phrase link cruft is fun. :)
Forum discussion at YouTube.