If you publish comics on Zestworld, you should see how your engagement data against each comic series and issue you've published.
For Comic Series

Total Readers: Number of unique fans that finished reading at least one issue
Email views: Number of unique fans (including subscribers) that viewed your comic series via email updates.
Email Open rate: Average of issue open rate for the whole series.
For Comic Issues
Web views: Number of views for your issue on the Zestworld site.
Email views: Number of views (subscribers & imported contacts) for your issues sent via email.
Email open rate: Percentage of fans & subscribers opening issues and issue teasers sent via email.