Turn was founded in 2004 to bring search efficiencies to online display. Today, Turn is commonly referred to as a Demand Side Platform (DSP), but is more accurately described as a software and services company with the industry’s only end-to-end solution for managing data-driven advertising. From media planning, buying, and optimization, to meaningful analytics, the world’s best advertising agencies and brands use Turn’s intuitive software to centrally control impression-level bidding and audience targeting across a range of the best inventory available; all in real time. And, boy does it work!

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You are asking the right questions! Love it.

Here is my 2 cents:

- On-site engagement: is the site engaging?…the pre-requisite is that it provides ways for people to engage (leave a comment, retweet something, post to digg) and then measuring how often people are using those.

- Off-site engagement: are people repurposing some/linking etc…

Here is a interesting post on a similar topic: http://blog.postrank.com/2009/11/measuring-engagement-of-the-social-web-2007-2009/

Virginie

eCairn