Well, from Encyclopaedia WOT, and aCoS - Edit 1
Before modification by rAndy aL at 28/12/2010 01:03:12 AM
I do not recall seeing any restriction of that kind on Skimming. You do not have to be 'very familiar' with the place you are going to - you just have to know where you want to go.
Skimming
The ability to open a gateway to a dark dimension (not well defined or understood), move through that dimension, and open another gateway back into the real world in a different location. First mention is TFoH,Ch6. Anyone of sufficient strength and knowledge can Skim. Skimming requires detailed knowledge of the place one is Skimming to. Skimming was not even known as a lost Talent. (ACoS,Ch9)
-Encyclopaedia Wot - Talents
The ability to open a gateway to a dark dimension (not well defined or understood), move through that dimension, and open another gateway back into the real world in a different location. First mention is TFoH,Ch6. Anyone of sufficient strength and knowledge can Skim. Skimming requires detailed knowledge of the place one is Skimming to. Skimming was not even known as a lost Talent. (ACoS,Ch9)
-Encyclopaedia Wot - Talents
What Egwene had pried from Moghedien was a way to journey from a place you did not know well to one you did. Slower than Traveling, Skimming was not even one of the lost Telents...
-A Crown of Swords - Ch9, p186
-A Crown of Swords - Ch9, p186
There would be more in The Fires of Heaven when Asmo was explaining things to Rand.