The question is a different one: How to you accurately measure usage time
For example, on the G+ time:
- Mobile use - how is it metered?
- Use through the Google Bar - how is it metered and attributed, if it does happen on a non plus.google.com
For example, for fair comparison:
- In Facebook, people writing personal messages are counted as using facebook. In the Googleverse, personal messages are attributed to GMail use.
- In Facebook, people watching a vid are counted as using facebook. In the Googleverse, vids can be watched on G+, but clicking on the vids titlebar will seamlessly transfer to Youtube. How is that time attributed?
For example, usefulness of the metric:
- In Google and Facebook, playing a game online is not really time spent interacting with Google or Facebook respectively with respect to the intent of the metric. Why is that time attributed as time spent at all?
How do you define a useful metric for site engagement that works better than the flawed 'minutes spent' metric?