The number of unique visitors present based on the time range you set in the above drop down.
The average amount of time a user is spending on your site based again, on the the date range which you send above.
The counts are based on the count of days a visitor sent an event for a certain number of days in the past month. Note that this calculation will always reflect last 30 days of usage (i.e. 30 days ago to today) for the set of visitors who were active during the time period specified.
Monthly if Active < 5 days
Weekly if 5 -12 days
Daily if > 12 Days
The time stamp of the most recent page load or click on your site from that visitor, regardless of if that page load or click has been tagged as an activity on your site or not.
The total amount of time the visitor has been on your site in the past 30 days. Like the "Number of Active Days" number, this starts last night at midnight, and goes for 30 days previous to that time.