VISIT

A series of one or more PAGE IMPRESSIONS, served to a validBROWSER, which ends when there is a gap of 30 minutes or more between successive PAGE IMPRESSIONS for that BROWSER.

SESSION

A series of PAGE IMPRESSIONS served in an unbroken sequence from within the site to the same BROWSER.

VISIT DURATION

The total time in seconds for all VISITS of two or more PAGE IMPRESSIONS, divided by the total number of VISITS of two or more PAGE IMPRESSIONS.

UNIQUE BROWSER DURATION

The total time in seconds for all VISITS of two or more PAGE IMPRESSIONS, divided by the total number of UNIQUE BROWSERS making such VISITS.

CHAT DURATION

The total elapsed time in seconds between the first and last time stamp recorded for each valid BROWSER'S CHAT IMPRESSIONS.

STREAM DURATION

The elapsed time in seconds between the first and last recorded file transmission for each stream sent to a valid BROWSER.

INTERACTIVE DURATION

The total elapsed time in seconds between the serving of an interactive file and any subsequent files to a valid BROWSER. NB: if no record of a subsequent file can be determined then the duration is deemed to be zero.