Commercial contacts.
More than 50M emails from 6M world organizations.
These data represent the following structure:
Grouping by country (top level domain) > Subdirectories by a first letter of an organization name > Files - names of organizations.
Each file contains a list of emails related to organization.
ac/a/acc.ac --------- name1@acc.ac /acs.ac name2@acc.ac ... name3@acc.ac /b/bea.ac ... /ber.ac ... /c/chr.ac /cic.ac ... ... ad/a/ada.ad /adv.ad ... /b/bib.ad /bom.ad ... /c/cal.ad /can.ad ... ... ...(the filenames are fictitious on the diagram)