LLLL Stand for 4 letter names like LLL is 3 letters.
Bacially to make it short, Speculation:
These names are short and easy to type and remember.
Companies ect.. (end users) would like to have the acronyms to make it easier to type & remember for internet surfers to find their website ect..
There is only a certain amount of 4 letter combinations available, once their gone, that's it. Well, their gone.
In reality, any combination of letters can mean anything to anybody at anytime. Some of the reasons why prices are higher for others is because of age, sound, rarity & letters that have the possibilities for more acronyms thus you have more leverage for a sale.
Take fkcj, it's all premium letters, no bad letters, but then it's further broken down by many domainers (reseller market) that K & J are semi premium not as good as F & C
Now if you look at fkcj.cn someone in china thought the domain was exactly what they were looking for, now IF they desire to have the .com that would make a possible end user sale that may be the same amount as say hypothetically, dapo a CVCV: Consonant/Vowel/Consonat/Vowel. Or not?
But in the Market dapo would sell faster and for much much much more money and that is because of what the market is dictating value to be.