What Happened to Small?

We went out for pizza here in Maryland yesterday. The interesting thing is that the pizza came in three sizes: medium, large and extra large. Now, I ask you. What happened to small? I'm sure in the UK you still have the sizes: small, medium and large but I'm now on the look out to see whether small is an endangered size in the US - at least as far as pizza go but it might extend to other things too. Maybe it's socially unacceptable now to only order something small? America!