I've seen tables with 10^3 and 10^4 columns if I remember correctly. As others have pointed out it's an efficient way to do timeseries, and as HBase tables can

I've seen tables with 10^3 and 10^4 columns if I remember correctly. As others have pointed out it's an efficient way to do timeseries, and as HBase tables can be broken into "column families", you may often associate many types of data with the same key, whereas in a relational database you're encouraged to split them into separate tables. Denormalized doesn't just mean duplicated.