Google Trends: ThomasNet vs. GlobalSpec

UPDATED: See clarification about 'Also visited' below.

Just announced that Google Labs' Website Trends tool can put graphs side-by-side. Hard numbers are not shown, which is probably smart on their part. And 'tiny' sites like companies in my industry don't have enough traffic.

So why not compare ThomasNet and GlobalSpec? This data I limited to USA users, since worldwide, the trends were nearly the same (and USA is my market). I also tried adding iqsdirectory.com, but not enough traffic to rank.

Thomas shows more traffic than GlobalSpec from USA visitors:

In the same screen they also show other sites their users visited. (Blue bar =TN, Red bar =GS)

TN's visitors must include a lot of their salespeople, as the #1 'also visited' site is their extranet. #3 Webtraxs.com is their website analytics tool.

UPDATE: Per a comment left at the site, this isn't exactly true summation on my part:
"A better way to think about it is the reverse: Nearly all users of TRRep.com visit ThomasNet.com, which makes perfect sense. This creates, statistically, a very tight association between the two. The point is that it has nothing to do with frequency, but with statistical probability."


Meanwhile GlobalSpec's visitors hit have a high probability of visiting ip09.com the most, which I am guessing must host their newsletter content somehow. Interesting to see trade-pub Machine Design as #2 'also visited' site.

Like any trend-graph, things are open for interpretation. What do you think this all means? Ultimately, I am looking at leads delivered, but this gives an overall idea of visibility.