I stumble across my best tools when my answer is no. As in Jennie Phipps asked the Freelance Success gang the other day if any of us have used Quantcast, and my kneejerk reaction was, “What the hell is a Quantcast?”

Followed by “Quick, download this for Good Stuff” and “I love Google.”

The short answer is that it’s a free audience measurement service for marketers and media sellers, which pretty much blankets the entire world economy. Like many consultants, this team loves big words:

• Comprehensive Visibility: We provide the most comprehensive visibility into Internet usage, both in scale and frequency, which creates the most holistic view of your customer. (Translation: We’ll tell you who visits your site.)

• Uniqueness in Audience: Because only Quantcast Lookalikes are built fro your data, your [stet] get the most specific and and unique picture of your consumers’ audience profile with us.  (Translation: Zoooom. You are suddenly talking 10 feet above my head here. Time to go for the trial and see if I can figure this out on my own. )

The day I tried to play with it, the site was in maintenance mode, which is fancy talk for “broken. Use one that’s already on the list.”

I chose IRS.gov because I had a sudden urge to know what kind of people voluntarily visit the IRS, even if it’s in cyberspace. Quantcast says 57 percent are female, with 32 percent between the age of 35 and 48. (Surprisingly, the 3 -12 year age range accounts for 3 percent of its visitors – lemonade stands must be a thriving source of income these days.) Most of the people who feel compelled to drop in on the IRS also check out the US Treasury’s site, Electronic Federal Transfers, Kiplinger and H&R Block.

No I understand why eTrade went with a talking infant in its commercials.

For the more patient among you, Quantcast has a full page of tutorials, a blog, and a press section with case studies and a newsletter.  Check out the terms of service as well – it’s more informative than the usual legal speak.