jecasc - 4:11 pm on May 13, 2010 (gmt 0)

I usually continue to display the product for some time, including a recommendation to a similar product with a link directing the customer to this product. How long depends on how popular the product was. Usually 3-6 month, because I sell consumable products and thats about the time it takes until they are used up.

The reason is this:
If I do not display the product the customer might look elsewhere for the product.
If I display the product with the information that the product has been discontinued there is a chance the customer will not look elsewhere - because who wants to buy a product that has been discontinued and has been in a merchants stock for who nows how long.
If I include a recommendation for another product I might still make a sale.