Unlike replying "cool" or similar, it does not infer that you agree or disagree or allocate it a positive or negative emotion, merely that you have noted it.
Interchangable with "nod", of which it is an intentional manipulation.
Use of both nod and nog prevents spamming of one reply and immediately informs the person being replied to that the user is awake and listening, not just nodding dumbly.
Nog replies can be used solely as an 'I understand' word in the form of "noggle". This is the inverse of "boggle", where you do not.
Bob: Ok, I've uploaded the re-written php and sorted all the tags out. The main vars have all changed, watch out.
I hate nogs they smell like shit and are grimey fucken niggers.