How does Time spent viewing email work?

[ARishi]

Hi, I noticed that Hubspot captures a metric called "time spend viewing email" that is broken down into 3 groups (at least 8 seconds, 2-8 seconds, less than 2 seconds).

1. How is this data captured across all email clients?  Do all email clients (e.g. Gmail, Apple Mail, Yahoo, Outlook, etc) provide this data, or is this data provided by only some clients and than extrapolated for all clients?  Which email clients provide this explicitly?  

2. Is Hubspot able to capture exactly how many seconds, rather than the 3 groupings that they provide today?  

[CHawkins · Accepted solution]

I haven't found any concrete answers to these questions but this thread has some good insights.

Generally, it is recommended to use these as "nice to have" guides but not rely too heavily on these as KPIs.