Historical clue formulations

• Chain email abbr. — 2026-01-07
• Inbox abbr. — 2025-04-30
• Email chain abbr. — 2024-01-07
• Subject line abbreviation — 2023-01-15
• Repeated string in a chain letter subject line — 2021-08-18
• Send on, as an email: Abbr. — 2021-08-10
• Abbr. in an email header — 2017-10-10
• Start of many a chain email — 2017-05-25
• Subject line abbr. — 2016-12-14
• Subject line starter on many an e-mail joke — 2009-04-07
• E-mail directive: Abbr. — 2008-02-10
• Pass along, as an e-mail: Abbr. — 2007-04-24
• N.B.A. position: Abbr. — 1999-07-24