What is www2? World Wide Web version 2?

Occasionally I come across some sites that have www2. instead of www.
Like this for ex:www2.blogger.com...
I may be paranoid,but I rather be paranoid than remain ignorant.
Is this some new version of the Web?

This is what i found

World Wide Web (www) was the original server for all information amassed through all sources. With billions of people and companies now using computers, www2 and www3 are in use. They are just other storage sites for information. I might have nothing but text on www, photos on www2 and graphics on www3, just to make it easier and faster to navigate.

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