I start to be annoyed with the "a power efficiency of 2 is the standard in datacenters". My servers are hosted in a datacenter with a global efficiency of 1.15, proved after more than a year in operation. Announcing that Google is doing 1.2 is simply announcing something wrong and I suppose Google is very happy with this number being provided to the press. It means that some competitor will use it as "Google is the best, they do 1.2, we are at 1.3 we are not too bad", where I bet Google is now near 1.1 or less (they operate without cooling in Belgium for example).
You're right -- those PUE numbers from the article were talking about their PUE at the time. Google's 2012 average PUE across all facilities was 1.12/1.13 with a minimum PUE of 1.09/1.10.
Also, Google puts enormous care into the process of calculating PUE since it's kind of black art and if you aren't careful you'll leave out some aspect of your operation that will mislead you into thinking your PUE is lower than it is.
PUE 2 probably was the standard when Google started building their DCs. There's a wide range between enterprisey DCs that consider going from 2 to 1.8 an epic win and clouds/hosters who are getting below 1.3. Google's PUE data since 2008 is published at http://www.google.com/about/datacenters/efficiency/internal/...
