It's number 2 actually - if sorted by value of trades during 24 hours, with 30% gap between second and third positions (bitcoin - 13M, doge - 2.7M, litecoin - 2M).

Impressive for a clone which was supposed to die few months ago (again - isracoin and auroracoin were released at the same time as doge and aren't even in top-100 now).