After the Web 2.0 tipping point, there is the rise of the question about appropriate measures with Web 2.0 (Ajax), Flash and RIA. In previous months there are several interesting posts that argues this question, such as the question about Web 2.0 measurement standards (Eric T. Peterson), Mark Baatse’s post about measuring Web 2.0, or the measurement replacement proposal by Steve Rubel.
When it is not talked about the online advertising models Page Impressions and CPM are already not used for KPI. Conversion and Return of Investment (ROI) are the measurement key phrases which explain an exact effects of online users’ actions.
I think that unique users per day and unique users per month are the measurements that can be used within the average time spent per user on the Web site. Those measurements are compatible with the measures in offline media and understandable for offline marketers (marketing agencies and marketing departments).
Issue about online measurement will be interesting for a long time, I think.