The point is publishing that constitutes good advocacy and implies expected future support for Go. A lot of people given the choice between learning multiple languages will factor a company like Google supporting and using Go in their decision.
I am sure if Google published on it blog that it rewrote some of its services in Nimrod, there would be a bump in popularity.
Of course it is implied that there is future support for Go since there are serious people behind Go who are Google developers but its current popularity comes from various implementations of the language and "rewritings" which are translated into blog posts rather than blog posts per se. I hope the difference i am trying to point out is obvious.
I am sure if Google published on it blog that it rewrote some of its services in Nimrod, there would be a bump in popularity.