What is an Active Directory?
Software
An active directory is a directory structure used on Microsoft Windows based computers and servers to store information and data about networks and domains. It is primarily used for online information and was originally created in 1996. It was first used with Windows 2000…
http://www.tech-faq.com/active-directory.html
What is an E-book?
Software
E-book is short for electronic book. They are also called ebooks and digital books.
They are simply electronic versions of real books which use devices such as a PC, mobile phone and e-book readers (e-readers) to read them.
E-books come in many file formats but many use HTML as the language used to describe the document.
There is no definitive E-book format which can cause problems if you ever change e-reader.
What is a web browser?
Software
A web browser is a computer program designed for viewing web pages.
There are many out there such as Internet Explorer, Firefox, Safari and Google Chrome. The most common is Internet Explorer followed by Firefox. Which browser to use is up to you and they all do pretty much the same job and work in pretty much the same way with an address bar for entering a web address, bookmarks for bookmarking your favourite sites and tabs for opening up many pages at the same time.
The chances are you will already have a browser installed on your computer.
What a browser does is take the basic language of the web (HTML) and make it readable by humans. The HTML document will be made up of text, and refer to images together with directions on how to show this information (called a CSS file). With all this data the browser then renders a page for you to view.

