Dedicated IP required for setting up a site?

as per one of Webmasterworld tutorial

[sandyk20]

can someone clarify my confusion here?
Why is a dedicated IP Address required to setup an active/large site/forum.?

My host, does not allows me to buy a IP, they need a proper reason for this.

thanks.

[FalseDawn]

Why is a dedicated IP Address required to setup an active/large site/forum.?

It's not required, but probably preferable for non-trivial sites. It _is_ required to install a dedicated SSL cert.

Just use your shared IP for now.

[gello]

They have a good reason for that, but you can do that with your shared IP