The scoreboard resizes itself to the values, but if the objective is longer then the values, it will resize only to fit the values.

http://c.oppy.me/YDLh20xl.png

I'd also like to address how strict the scoreboard is, such as being unable to create a few small lines of text with info (also the max 16 character limit), or make a custom title for players under their name, or display something like health (on servers) I know it's not meant for that, but it would open up a lot more usages for modders, map makers and server coders.