IIS (Web Hosting) quotas explanation:
Web Sites - Amount of websites allowed for customer's hosting space.
Web App Gallery - Allows to use Web Application Gallery.
ASP - Allows to use Classic ASP
ASP.NET 1.1 - Allow to use ASP.NET 1.1
ASP.NET 4.0 - Allow to use ASP.NET 4.0 and later
ASP.NET 2.0 - Allow to use ASP.NET 2.0
PHP 4.x - Allow to use PHP 4.x
PHP 5.x - Allow to use PHP 5.x
Perl - Allow to use Perl
Python - Allow to use Python
CGI-BIN Folder - Allow to have CGI-BIN Folder. CGI-BIN historically was the only place where executable or script code (binaries, shell scripts, etc.) could be stored. It is mostly a historic relic since most hosts allow execution of scripts from anywhere.
Secured Folders - Allows to have Secured Folders. Secured Folders are folders with access by user/password.
Shared SSL Folders - Allows to use Shared SSL Folders. This is useful if you need to have SSL Encrypted pages but do not wanto to buy additional SSL certificate for your domain.
Web Sites Redirection - Allows HTTP redirection.
Changing Site/VirtDir Home Folder - Allows to change website or virtual directory home folder from default to anything else.
Virtual Directories - Allows to use Virtual Directories.
FrontPage - Allows using Microsoft FrontPage. Requires FrontPage Server Extensions to be installed on Web Server.
Custom Security Settings - Allows to manage write permissions, anonymous access, basic and windows authentication.
Custom Default Documents - Allows default document management.
Application Pools Restart - Allows to restart website's application pool.
Dedicated Application Pools - Allows to create dedicated application pool for website.
Custom Headers - Allows to create custom headers.
Custom Errors - Allows to manage custom error messages.
Custom MIME Types - Allows to manage custom MIME types.
ColdFusion - Allows to use ColdFusion.
ColdFusion Virtual Directories - Allows to have ColdFusion Virtual Directories.
Dedicated IP Addresses - Allows to assign dedicated IP address(es) to website.
Remote Web Management - Allows to enable and configure IIS Remote management access.
SSL from Let's Encrypt - Allows to request SSL Certificates from Let’s Encrypt and apply to a website.
SSL - Allows to apply SSL certificat to a website.
Allow IP Address Mode Switch - Allows to switch between shared and dedicated IP address.
Enable Hostname Support - Allows to use hostnames (also known as host headers or domain names).
App pool max CPU usage (1/1000ths of one percent) - Allows you to control the amount of CPU a website can consume.
App pool max CPU usage under load (1/1000ths of one percent) - Allow you to control the amount of CPU a website can consume under load.