Subjectivity 1.0 - Resurrects Subjects Laid at the Ground by Oversight

"That which lies at the ground": a translation of Aristotle's hypokeimenon lies at the ground of our subject. It used to mean the substance that carries the ever-changing attributes, something about which one of my old teachers could talk for hours on end.
I cannot. I can, however, point to a tool that, should your email's Subject: lie at the ground, reduced to not even filth, can re-erect it:
›› Subjectivity warns you when you are about to send an email with a blank Subject: line from Mac OS X Mail and can insert your message's first words in it automatically. (Mac)