Doodles Are "Designer Dogs" -

Doodles are called designer dogs because their parents come from two different breeds of purebred dogs, that have been cross bred for a specific purpose.  

Most Doodles come in 50/50 mixes, 75/25 mixes or 25/75 mixes depending on whether hybrid vigor, hypoallergenic properties, or size reduction is the primary objective.

They have been created or "designed" by cross breeding some of the world's most popular dog breeds either to reduce the common health problems of certain breeds, to reduce the amount of shedding (and the allergic reaction to all that hair) of some breeds, and in the case of mini-doodles; to reduce their size, making them more suitable for life in a smaller home.

The common factor of all Doodles (and Whatch-ma-poos) is that they have been crossbred with poodles, either large or small depending  on the desired size of the Doodle (or the Poo)..  

Yuck! Did I just say "depending on the desired size of the Poo"?