What are independent bookstores really good for?

Here is my new Slate piece.  Excerpt:

If you don’t like the superstores, it is easy enough to expand your
viewing horizons through other means. Just go to new sections of your
superstore (the best popular book on geology, gardening, or basketball
is very good, whether or not you like the topic). Stoop or
stretch to slightly uncomfortable levels. Use the stool. Peruse books
randomly. Look at other peoples’ discard piles. Spend more time in
public libraries, which offer many of the best features of indie
bookshops, including informed staff, diversity, and offbeat titles. Of
course, public libraries aren’t exactly atmospherically "cool." The
clientele is often young children, women over 40, and retired men. I
visit five public libraries on a regular basis, and each one makes me
feel old. But they deliver the goods.