"Readers may be divided into four classes.
1. Sponges, who absorb all they read, and return it nearly in the same state, only a little dirtied.
2. Sand-glasses, who retain nothing, and are content to get through a book for the sake of getting through the time.
3. Strain-bags, who retain merely the dregs of what they read.
4. Mogul diamonds, equally rare and valuable, who profit by what they read, and enable others to profit by it also."

Mr. Coleridge, 1811ish. I fear that I currently fall into category #3. You?