[mebassett]

I think he's talking about growth in the features (dependant variables) of your dataset while keeping the number of independent observations constant; not growth in the dataset due to new independent observations.

I think he's correct in discussing it - I find folks propose new features far more frequently than new observations become available.

[Fede_V]

When people talk about big data, they usually discuss datasets with lots of observations (aka, rows). Not datasets with lots of features but few rows - those are far more common in fields like genetics or omic sciences in general.