More critically their LINPACK score wouldn't be very good (at least relative to the number of cores they have). By HPC standards Google does not have a sufficiently high performance network. It is no accident that InfiniBand commands a considerable share of the list. 30% overall, >50% of the top 10, and the *ONLY* open interconnect in the top 10 at all.
For instance the first Ethernet system (well, actually an Ethernet/IB hybrid) is number 16, with 30240 Nehalem 2.5GHz cores gets only 168TF, while number 10, with QDR IB gets 274TF out of its 26304 2.8GHZ Nehalems.