Final answer:
Outlook and Thunderbird are both widely used desktop e-mail programs, with Outlook part of Microsoft Office and Thunderbird being open-source from Mozilla.
Step-by-step explanation:
Outlook and Thunderbird are two popular desktop e-mail programs. Microsoft Outlook is part of the Microsoft Office suite and has been widely used for business and personal purposes. On the other hand, Mozilla Thunderbird is a free and open-source email client provided by the Mozilla Foundation. Both offer various features for email management, including organizing emails into folders, filtering spam, and supporting multiple email accounts.