[ZeroCoin]

"doesn't immediately qualify it as spam", no. That's correct.

It does however make it very difficult to gauge who is a legitimate linker and who is not.

All I'm really saying is if you're starting now with all of the years of random linkspam backscatter is that you are in for a rough ride.

[TomAnthony]

Even if you have had a perfect history of when links appeared you're still in the a rough ride. Furthermore, absence of the that information doesn't invalidate the author's approach (but having it might improve its effectiveness).

As an aside, you have use Ahrefs.com to get pretty decent tracking of when links appeared since it started (I think ~18 months ago or so). Given that the rate of spammy pages is increasing extremely fast and old spam pages are dying off, I imagine that in the not too distant future you'll be able to get decent link history for many sites.