Obligatory Preamble:

Microsoft Outlook or Outlook (full name Microsoft Office Outlook since Outlook 2003) is a personal information manager from Microsoft, and is part of the Microsoft Office suite.

Although often used mainly as an e-mail application, it also provides a calendar, task and contact management, note taking, a journal and web browsing. It can be used as a stand-alone application, but can also operate in conjunction with Microsoft Exchange Server to provide enhanced functions for multiple users in an organization, such as shared mailboxes and calendars, public folders and meeting time allocation.

Security Issues:

One of Microsoft's goals is for the e-mail client to be easy to use. However, the embedded automation and lack of security features compared to competitors have been repeatedly exploited by malicious hackers using e-mail viruses. These typically take the form of an e-mail attachment which executes on the user's machine and replicates itself by mass-mailing the user's or Exchange server's address list. Examples of such viruses are the Melissa and Sobig worms.