More like acronyms, I'd say. For example, "HTTP" = hyper-text transfer protocol.

It's funny that the word 사자성어 (meaning: 4-character idiom) is itself a 4-character idiom. East Asians like 4-character groups so much, they even read numbers in groups of 4 digits. For example, 1,234,567,890 would be read 12 억 3456 만 7890.

I doubt they like it. 4 is considered unlucky in East Asia. Elevators always read 1->2->3->5->...

http://en.wikipedia.org/wiki/Tetraphobia

Although 4 is considered unlucky in Chinese, decimal numbers is represented in 4-number groups, instead of 60 thousand, we'd have 6 wan, 800 million would be 8 yi, etc