typographic marks

There are many typographic marks which are familiar to most, but understood by few. Most of these glyphs have interesting histories and evolutions as they survived the beatings given to them through rushed handwriting of scribes and misuses through history. They now mostly live on our keyboards and in our software, and a few are used often, so it seems only fitting to know where they come from and how to correctly use them.
http://retinart.net/typography/marksunknown/