My understanding of premium is as follows:

1. extensively high demand (not necessary one word, it could be a two word domain)
2. one word dictionary domains
3. 3 letter domains


I do not think that 4 letters could qualify as premium unless there is some meaning or high demand and same goes for 3 letters too.

I mean who cares about cky or zqm. But certainly luv, zip are better 3 letter domains.

Let us know what other people on forum thinks.

Domain7