Interesting thought of 37Signals’David Heinemeier Hansson on the sustainability of e-mail (and other electronic communication):
It’s interesting to see certain emails decay in importance in your inbox. On day one, you feel you must keep it. On day 7, <delete>.
— DHH (@dhh) October 31, 2012
In German this is called: DELLE: Durch einfach liegen lassen erledigt.
In email marketing land this is called: be relevant or be forgotten.