Postions are counted every time.
Airframes ( aircraft) are counted once a day.
From the FAQ:
Why do the hourly aircraft counts on my ADS-B site’s statistics not sum to the daily aircraft total? SHARE | BACK TO TOP
An aircraft is counted only once per UTC day to calculate the daily aircraft totals. A given aircraft is counted only at most once per hour for the hourly totals.
For example a medic helicopter nearby can make multiple flights a day and record multiple postions everytime but the aircraft itself is only counted once to the total numer of aircraft.
Other refers to messages that are received but incomplete so they are in a different section. It could be missing height, speed, heading etc.