Online auction great eBay publishes a marketing calendar and updates it frequently throughout the year. This calendar lists approximate dates for it’s special merchandising promotions - for example, when books might be featured, or consumer electronics, or swim wear. This can help both buyers and sellers. It will help buyers to plan when they do their shopping for certain items, and sellers in planning when to sell them. So - it’s a win-win situation for everyone (including eBay, which makes money from fees both ways!)