Why turn GZip compression off or on? and so on?

[CaribeJoe]

The CP settings offer a yes or no for GZip. The settings also say that Zlib needs to be installed.

Use GZip compression
"Zlib" needs to be installed on your server

That introduces questions that seem to not be addressed either in the setup instructions or in a Help file either on the site itself or here in this support forum.

Why would a site owner choose to install GZip or not?

Are there alternative programs that one might use?

What are their relative merits?

What is Zlib?

Exactly where must it be installed?

Are thri any configuration issues for either of these items?

[V@no]

GZip compression does compressing "output" pages on the server while being sent to a client, that makes transaction faster. Client's browser must support such a feature (most modern browsers support it) and it decompress received page and shows it to the user.
I probably wont be "too wrong" if I compare this feature with Dialup connection to internet. Because 56k with v.90, v.92 and so on compression algorith does the same thing - fist compress requests and sents to the server then decompress received information and shows it to the user.
the only back-draw is that takes little more server recources to compress, and client recources to decompress, but if u have atleast "minimum" updated computer u wont be able even notice any slowing down.

[Shap]

thanks for explaining it, I didnt have it on, now its on 9!