What is bounce rate?
The bounce rate (or more optimistically click through rate) is a measurement of how far visitors click into your site.
Bounce rate: The percentage of visitors who visit your web site and leave without getting any further than one page (bounce).
Certain statistics (like bounce rate) are "undefined" until all the users events have elapsed. i.e. the depth of page views (amount of clicks) of a visit is not defined until the visit is over.
The Bounce rate reported in Opentracker tells you the number of visitors, as a percentage of the total, who click away after each page.