Aug  6 17:33 2004 from Josh 
An espresso macchiato can best be described using related drinks.  An 
espresso is just espresso, no milk.  As such, a single should be between 
.75 and 1.5 ounces, the most common being 1 ounce (for the purpose of 
later proportions, I'm just going to proceed under the assumption that a 
of espresso shot is one ounce). 
  A cappuccino is a drink of thirds: 1/3 espresso, 1/3 steamed milk, 1/3  
textured foam.  As such, a single should be about a three ounce beverage, 
and a double should be about 6 ounces. 
 A latte is a recent invention, and it loosely covers anything with more  
milk than a cappuccino.  A mocha is a chocolate flavored latte. 
 So, back to an espresso macchiato: It falls in between an espresso and a  
cappuccino.  Traditionally, it would just be an espresso marked with 
steamed milk (which is what "espresso macchiato" means: marked espresso). 
It is not uncommon (and I think not misleading) to pour in a small amount 
of steamed milk.  In order to maintain a separation between drinks, it 
should really be less than 1 ounce of steamed milk.  At one ounce, it 
would be more properly described as "A cappuccino with less foam".  At 
more than 2 ounces, it's a latte. 
 This is what the terms mean, but sadly most cafe owners (to say nothing  
of most baristas) can't be bothered to read up on these things, so what 
you actually get when you order these things varies from shop to shop.  I 
would advise ordering nothing other than a latte at most places; bad 
espresso doesn't taste good. If it's really bad, perhaps a flavored latte 
to cover up the taste of the coffee. If the espresso is good, on the other 
hand, it's a shame to get anything more milky than a cappuccino, as the 
taste of the coffee becomes overwhelmed by the taste of the steamed milk. 
  I was using espresso macchiato as a testing beverage because it's easy  
to screw up, so it tends to be a good indicator of overall process 
quality.