Robert_Charlton - 5:48 am on Jan 5, 2012 (gmt 0)
SEO Spyglass used to rely on Yahoo Site Explorer for their database of links. Now they say they are using a new database.
They apparently now have their own database, recently launched, which they use in conjunction with other data they pull from "multiple link sources".
This is all fairly new. Eric Covino at SEObook gave it a thoughtful review, and I'm going to take the liberty of linking to it....
SEO Spyglass Review: A Brand New Link Source
The launch of a third or fourth-ish link database (Majestic SEO, Open Site Explorer, A-Href's rounding out the others) is a win for link researchers. It still needs a bit of work, as we'll discuss below, but hopefully they plan on taking the some of the better features of the other tools and incorporating them into their tool.
The tool is also mentioned in our Google SEO forum's current thread...
Favorite SEO Tools
Note that the subscription price for the SEO Spyglass tool is a bit complicated, and there's a slightly heated exchange on our thread about what it does cost.
I've been very impressed by what I've seen of the new interface on the Majestic tool. I say that, though, not yet having had time to try it myself.