Personally I think NNN.TV is pretty worthless to anyone from a country which speaks English or a major European language. What company is going to brand a video-oriented site on 631.TV? It makes no sense. Maybe in China but not in the US.
LL.TV I get...
SA.TV = San Antonio
NY.TV = New York
MB.TV = Miami Beach
LA.TV = Los Angeles
RE.TV = real estate
BB.TV = basketball or baseball or bodybuilding
LLL.TV - I guess there are three-word phrases but this would be less common than two-word phrases. Note however that many airports have three-character codes so a LLL.TV might be a means of representing that region.