.com :-Utilized by all entities, as its rules of ownership are now unrestricted. The most popular and one of the oldestTLDs, .com was intended for commercial use only.
.net:- Intended for computers running at network providers. Today it is used in an unrestricted fashion, and many times becomes the second-choice TLD if .comis not available.
.org :-Intended for nonprofit organizations. Used by commercial and noncommercial sites.
.edu :-Used almost exclusively by post-secondary institutions in the United States.
.gov:- Used by federal, state, and local government departments within the United States.
.int :-Used only by international treaty-based organizations.
.mil :-Used by the U.S. Department of Defense.
.biz:- Intended for commercial business entities. Was created to allow for an additional domain name pool due to thesaturated .comnamespace.
.info:- Intended for informational sites unrestricted TLDs.
.name:- Intended for personal use only.
.pro:- Intended for professionals in various professions, including doctors and lawyers.
Extension Index size
.com 20,400,000,000
.org 2,290,000,000
.net 2,110,000,000
.edu 248,000,000
.gov 232,000,000
.info 227,000,000
.biz 74,300,000
.cat 35,800,000
.int 8,230,000
.mil 8,130,000
.name 7,000,000
.travel 6,310,000
.coop 646,000
.aero 646,000
.pro 600,000
.museum 480,000
.tel 248,000