Letter = L = Alaphabatical Letters Character = C = Alphabatical Letters OR Numbers Number = N = Numbers
NNLL.com and CCCC.com both are same. But still I understood the question. I think 4 characters .com have no value right now. But if there is some catchy one then you can surely put your money on it.
The value would largely depend on what it can stand for. R2D2, UB40, and 1040 (US tax form) would have more value than 'random' combinations.
yes i have a few 4 letter domains that i think the name has sum value uR24.com Ru01.Com uR20.Com then i have another that only has value with a idea yfpp.com what can i dont with that nothing that i know of! dont know why i have it!
yap. probebly ,most of them having lower quality letters like Q,X,Y,Z. lots of ppl dont like to register those names. and all other llll.com domains are registerd. therefore llll.com has a value. but not sure about cccc.com. because probably lots of cccc.com avalable to register.
I think it comes down to this: so far, the number of availability is great and the demand isn't quite there. Therefore, they're probably not worth regfee.