I'm getting Twit-fatigued from all of the phenom Tw-stats, but I can't resist pointing out how Nielsen's May 2009 report on Twitter usage illustrates the problems with using average time on site as a rough gauge of engagement.
Nielsen reported that the average time per person on Twitter in May 2009 was a little over 17 minutes, an increase from about six minutes in May 2008.
This is an average. This means you don't know how many people spent 20 hours a day on Twitter, and how many spent zero.
We do know, from a recent Harvard Business Review report, that:
- the top 10 percent of "prolific" Twitter users produce over 90 percent of all Tweets, and that
- the median number of lifetime Tweets per user is only one!
My advice: Don't use time on site as an indicator of success unless you're willing to really dig into your data and segment out heavy users vs. light users.
Here are two more observations – bashes, really – on using time-on-site.