The terms F1, F2B, etc. specify the generation of the Goldendoodle, as detailed below.
First Generation (F1) Goldendoodle: Golden Retriever + Poodle
First Generation Backcross (F1B) Goldendoodle: F1 Goldendoodle + Poodle
Second Generation (F2) Goldendoodle: F1 Goldendoodle + F1 Goldendoodle
Second Generation Backcross (F2B) Goldendoodle: F1 Goldendoodle + F1B Goldendoodle OR F1B Goldendoodle + F1B Goldendoodle
All further crossings are simply referred to as multigenerational.
Depending on the coat types of all the parent dogs in a breeding if they have the wavy thin coat such as a lot of F1b wavy coated dogs have; then they are crossed back to a poodle to get the fuller coat and still be the wavy to curly shag looking coats; the F2b coat types have quickly become the preferred coat type of my customers as 95% of the F2b puppies get the wavy to curly shag looking coats and illuminates the curly coats. Its all in the genetic testing to design the coat type and figure out if the parent dogs have inherited more GR or Poodle.
Additional information on generation breeding is available at http://www.goldendoodles.com/faqs/generations.htm