Littera Scripta (Popularity: )
http://www.litterascripta.com/ Antiquarian, used & rare books on the Internet: A Reader's Guide. Includes resources for readers, book collectors, and booksellers.
Book Hunter Press (Popularity: )
http://www.bookhunterpress.com/ Book fair calendar, dealer search capacity, used book market reports, and print and subscription online regional used book lovers' guides.