Modern server computers are so powerful nowadays that they generally have a large degree of spare computing power.

Rather than buy additional servers, it is possible to create several virtual servers on one physical server. Each virtual server is allocated a slice of the available computing power.

As well as providing efficiency savings by reducing the need to buy more hardware, virtualisation also enables one physical machine to run several different operating systems. Therefore a Windows server and a Linux server can run on the same machiine.

Special virtualisation software supplied by companies such as VMWare is required to run several virtual computers on one physical machine.

sudo is short for Super User Do and is a programme that enables users of linux and apple mac systems to run certain command with administrative priviliges. It means that the user doesn't have to log in to the computer as the administrator in order to carry out a command.

It is called from terminal and is most commonly used when installing new software.

Safari is the web browser supplied by Apple with it's Mac OS X operating system. It was first released in 2003 and Safari 3 became available for Windows (as a beta) in 2007.

It is now used on Apple's mobile devices including the iPhone and iTouch. It uses the open source project WebKit as it's foundation.

Opera is a web browser first publicly released by the Norwegian company Opera Software in 1996. It is available for many types of computer operating systems including Windows, Mac OS X and Linux.

Although not very common on desktop and laptop computers, it is very popular on mobile phones and PDAs as well as being the web browser for the Nintendo DS (a mobile games device) and the Nintendo Wii (a home games device).

This is the process of setting up fake blogs in order to promote other web sites which carry advertising and generate revenue for the person who creates the site.

These fake blogs are know as splogs which is a short for spam blog.

Someone who creates a splog splogger.

Splogging often involves taking content for another website without the permission of the owner and republishing it.

At the risk of disappointing all the accountants in the room, this is not the State Earnings Related Pensions Scheme.

When you use a search engine such as Google or Yahoo and enter a search term, the results that are returned to you are displayed on a SERP.

It simply stands for Search Engine Results Page. It's just yet another pointless acronymn designed to make you feel like you don't understand the internet. People understand perfectly well if you just use the term "results" or "results page" when talking about search engines.

A SERP usually consists of about 10 links to websites that are most relevant to the search phrase or word that you used. They will usually also contain small advertisements. These are generally placed in a column on the right hand side of the page.

The 10 or so most relevant search results are know as "organic results" where as the advertisements are know as "paid results".

This refers to the amount of space available on a screen.

When publishing something in print, the size of the paper is known and therefore how something looks in print is entirely predictable.

A web site is not like that. Different computers have different display resolutions depending on their age and manufacturer and this affects how much of a web site can be seen on screen at any one time.

Add to this the fact that not all internet users have the window of their web browsers maximised, can resize the window are and can configure their web browser to show different toolbars and this means that the amount seen in one "pageful" varies greatly.

A screen reader is a piece of software interprets what is currently on a users computer screen.

The screen reader reads aloud what it finds on screen or outputs what it finds to a braille keyboard.

Screen readers are mostly used by people that are blind, have a visual impairment or a learning disability.

It is important that web sites are built in such as way as to be accessible to screen readers and their users.