Well this just tells the npm client to download the modules from official registry which is "
https://registry.npmjs.org".
Extra info: If you want even faster downloads within an organization(or wherever recurring npm install might occur), I would recommend setting up a local lazy mirror.
PS: I maintain one such lazy npm mirror app-
https://github.com/bhanuc/alphonso . It only stores the modules that has been requested and makes subsequent installs much faster.