How are "targeted visitors per month" counted?

​What are the "visitors targeted per month"?

The number of targeted visitors is the number of unique visitors who saw at least one survey during that month. This is similar to impression counting in advertising. 

Who is counted?

The number of visitors who saw at least one survey, regardless of whether they interacted with it or not.

Who is not counted?

Visitors who visited a page where a survey is configured to run, but no survey was displayed during their visit.

What do we mean by "month"?

The counter resets in the beginning of your billing month, not calendar month. For example, if you signed up for a plan on January 9, the counter of targeted visitors will reset on the 9th of every month. There is no carry-over from prior months, the counter resets even if you did not max out the number of visitors you can target.