Historical clue formulations

• Eye-grabbing email subject line — 2022-11-13
• !, in emails — 2022-06-30
• All-caps word in an email subject line — 2018-11-27
• Subject heading for an important email — 2016-05-31
• Pressing — 2015-09-05
• Requiring immediate action — 2012-07-03
• Pressing — 2009-02-19
• Burning — 2008-10-04
• Like overnight mail — 2002-05-11
• Like a FedEx package — 2000-11-26
• FedEx notation — 2000-09-11
• Pressing — 2000-04-08
• High-priority — 2000-01-31
• Word on express mail — 1999-11-01
• Pressing — 1995-05-13
• Memo word — 1995-01-08