Firms are also marketing themselves differently to job candidates, says Rosemary Haefner of CareerBuilder, a popular job-search website.

In her first letter to Marks &Co., Helene Hanff encloses a wish list, but warns, "The phrase 'antiquarian booksellers' scares me somewhat, as I equate 'antique' with expensive."

The Motoyas hail from Fukui, a rural area on the Sea of Japan, where they met while working at a small local credit union, according to Ms. Motoya's autobiography.