From memory example, Aeon Wide was hitting about 500 downloads per week peak when it became a hot skin, and that was without the updates on forum or getting from svn, Xface has had 163558 downloads and is the top Hot skin.when is a skin complete? it's compatible with many modules/plug ins. and it's downlaoded a lot.
and what's a lot?
Skins are monitored for all the above criteria's, when reached for a period of time, then the skin is promoted.
I'm sure cul8er will make it