I'm interested in how/why a couple of the biggest channels on Freenode have been left out: #bitcoin-otc with 484 nicks and #bitcoin with 1179 nicks at the time

I'm interested in how/why a couple of the biggest channels on Freenode have been left out: #bitcoin-otc with 484 nicks and #bitcoin with 1179 nicks at the time of my post. What gives?