how do you get a domain that starts www2 (or similar)

I have seen domains starting www3. or ww2. how exactly do you get these?


thanks...

 

Sites that need additional servers to handle their web traffic setup additional servers to handle the load. Often they name them like that. The "how" is either a separate server or separate hosting account and using DNS ("A" records, round robin, etc) to point each subdomain to a different server.