The practice of blind carbon copying (BCC) in Microsoft Outlook allows a sender to include recipients on an email without revealing their addresses to other recipients. This is useful for maintaining privacy, particularly when sending messages to large groups or external contacts. While there is no universally fixed technical limitation, practical limitations exist.
Using BCC offers several advantages, including preventing reply-all storms, safeguarding email addresses from spammers, and complying with data privacy regulations. Historically, BCC emerged as a crucial feature as email communications became more widespread, addressing concerns about privacy and etiquette that were not adequately covered by traditional CC (carbon copy) functionality.