Generally, both individuals and enterprises are free to choose which domain extension they want to use for their websites. There is really no clear cut answer to who should use which. Nonetheless, some TLDs have just become more popular for specific uses or industries.
.COM - is the most popularly used gTLD. It may be used for both commercial and personal use.
.NET - though there are no rules, this domain extension is more often used by internet companies.
.ORG - if you belong to a non-profit organization or a trade association and you want to set up your own website, this is the recommended domain extension for you.
.INFO - if you want your website to be known as a place to find informational resources, then it would be the best TLD.
.BIZ - as the name suggests, this is mostly used for commercial and business purposes.
Using Country Code Top-Level domains like gTLDs have no definite rules as domain extensions. However, those who choose to use ccTLDs are usually individuals or organizations which products or website resources are particularly targeted to a specific country. Domain owners may benefit from using country specific domain extensions using improved local search engine rankings and a stronger relationship with local clients.