Why does a domain name start with www?

Question

Computer networks

Hello everyone,
Today, when we set up a redirect from example.com to www.example.com in nginx, I asked the team leader why not the other way around? He replied that it was so generally accepted and gave the example of the buzz and Facebook. I began to check the addresses of sites that I often visit and the same Yandex does not redirect to www. So I wondered why the main domain is often a domain starting with www?
I couldn't google the history of this issue.
Thank you.

Answer 1

Historically.
The web server was supposed to be just one of the servers that hang on your domain name.
For example, there is a company with the domain company.com
www.company.com - the website of the company
smtp.company.com and pop.company.com - the mail server of the company
ftp.company.com - the file server of the company
ns.company.com, jabber .company.com, irc.company.com and so on - a bunch of other services from the same company.
In practice, today most sites are just sites, they do not have any other services. Very few people keep their own public mail or file server. So company.com === www.company.com

Answer 2

The reason is purely historical. Now it doesn't make sense. It only creates more problems. Usually they just do CNAME on it and that's it.

Answer 3

It was just accepted that way, but in fact there is absolutely no difference. I make all sites without www

Answer 4

Because world wide web was originally an abbreviation for web resources.
At the dawn of the Internet, other services were much more popular - irc / email / telnet / ftp, and then http appeared and was called the world wide web, so domains with www were made for it.
Historically.