Short vs Tall Cocktails

Tall cocktails generally refer to cocktails served with more mixer and less alcohol in tall glasses. The exact amounts vary by barkeep. Short cocktails are served in short, wide glasses with less mixer but the same volume, not just because of general understanding of the definition of a short drink, but also because both professional bartenders and normal people are more likely to pour too much alcohol in short glasses. Despite the fact that short glasses contain more alcohol, tall drinks often cost more.

http://www.eurekalert.org/pub_releases/2005-12/bmj-sgm122105.php
http://drinkoftheweek.com/blog/cocktail-q-a-tall-drinks/