significance of valid on date while creating Org Unit

hello all,

i have created an Org Unit through PPOCE

here the object Divisional Engineer has valid dates from 01.01.1950 to 31.12.9999 which i have entered while creating the objects,

how ever in screen shot one what does the date 07.09.2016 signifies (what is meant by valid on here),

thanks all.