Back in college (for me the 80s), I learned that storing table data in rows would greatly increase performance due to high seek times on hard disks. SELECT * FROM table WHERE ... could read in the entire row in a single seek. This was very valuable when your table has 100 columns.

However; a different query (e.g. SELECT name, phone_number FROM table) might result in fewer seeks if the data is stored by column instead of by row.

The article only seems to address data structures with respect to indexes, and not for the actual table data itself.