Download-monitor is a software used to find Internet /Download usage.Internet usage mean if you are browsing Facebook or Watching YouTube or in any activity on the web,Download monitor will monitor your Data usage.So you will get detailed report in every seconds.You can find How much data downloaded in each seconds,each Hour ,each Day or in Total.So you will get awareness of day to data internet usage.This will helpful for those have limited Internet connections.After watching several Videos in YouTube you can check how much amount has downloaded.So i believe that this is a Must Have software for Ubuntu.