Actually that's what I thought, but it's not always the case. Sometimes a good chunk of the TEXT type column is saved in the row itself (~768 characters), and when the length exceeds that, the remainder is stored in the blob area of the table store. (http://www.mysqlperformanceblog.com/2011/04/07/innodb-row-si...)

This depends on your row format, an obscure technical issue most never have to deal with, but it can be a problem.