You must also know the type of web hosting that you need.  Depending on the type of

Shared Hosting

Shared hosting in recent years has become the norm.  A shared host has multiple websites hosted on one server that typically is only running one instance of the operating system.  Some shared hosting platforms will host hundreds and possibly even thousands of websites on one server.  This is called overselling i.e. if everyone used their alloted resources the server could not handle it.  However, in most cases a large portion of the websites are never or hardly ever utilized so there is plenty of shared resources available for a site that needs them.  Shared hosting platforms have a set amount of resources one website can utilize at a time and often a host will suspend your account if you max out your allotment too frequently.  The biggest pro for shared hosting is the price.  For just a few dollars a month you can have a website up and running and generally have decent customer support and help when you need it.  Shared hosting is recommended for most do-it-yourself type personalities and companies where you do not need to staff an admin to run your server.  The host takes care of the software and hardware updates and all you have to do is worry about your site.

VPS Hosting

Virtual Private Servers are sectioned off units on a server.  What this means is that one physical server is sectioned off into multiple Virtual Servers.  Each virtual system is running its own operating system or virtual machine environment.  This allows you to have a set amount of dedicated resources for your website and files.  VPS servers are good for mid-sized websites where the load, number of connections and CPU resources are higher than what a Shared Hosting account will provide.

Dedicated Hosting

Dedicated servers are needed when you are running large database driven websites or sites with very high amounts of traffic, images to load or products to sell.  A website like Yahoo is running on multiple servers whereas something like our site can run great on a shared hosting account.  A dedicated server also gives you higher amounts of access to the server and its configurations as well.