Outlook Express

E-mail client and newsreader developed by the software supplier Microsoft. Included as part of the Internet Explorer web browser package built into the Windows operating system, it can connect to a variety of e-mail systems using simple mail transfer protocol (SMTP), post office protocol 3 (POP3), internet message access protocol (IMAP), and hypertext transfer (HTTP) protocol.

Outlook Express can be used to read newsgroups and discussion groups by using network news transfer protocol (NNTP) based news servers. Newsgroups and e-mail can be configured for multiple users on one personal computer, and information can be downloaded for viewing later when offline. Because of its widespread use, Outlook Express has been the target of numerous viruses that extract contact information from the Windows Address Book and pass themselves on to other machines.