Disk space: The amount of disk space you need depends on the mega bytes (MB) of the files you upload and the size of your email accounts. You need also some disk space for log files + web statistics that are automatically created in your account. Most webhosters offer more diskspace than you ever need.

Data transfer: Data transfer is the measure of the traffic generated from your website. Data transfer is measured in bytes, kilo bytes (KB), mega bytes (MB) or giga bytes (GB). About 80% of websites on the internet uses less than 5 GB of data transfer per month. An average website uses less than 250MB of data transfer per month and receives about 50 visitors per day. Websites with image galleries use more data transfer than is a regular ones, but seldom more than 2 or 3GB per month. Only very popular sites exceed 30GB data transfer per month (This one uses an everage of 35GB per month).  This is how you calculate data transfer: Visitors x Page size (html+images) x Page views (number of pages) x 30 days = Monthly Website Transfer. Your email traffic is also counted as data traffic.

Uptime: This is the time your website is available on the internet. 99,9% Is the most common level offered. 100% Uptime is impossible since all webhosters have to perform maintenance on their servers ones in a while and technical difficulties can occur. Most large webhosters have back-up servers and back-up internet connections (backbones) to minimise downtime. 1% Downtime means that your website is unavailable for 8 hours in a month. Often you can't use your email either during this time. The webhosters mentioned below all have an uptime of 99,9% or higher (measured by independent websites). 

Multi domain hosting: If you have more then one domain name and want multiple websites with their own domain, multi domain hosting is the cheapest choice since you have to purchase only one hosting package. The cheapest webhosters (like dot5hosting) might not offer seperate email accounts for the additional domains.