Make Marketing Interesting.
The resurgence of sales that follows an artist's death is just one example of the social aspect of consumption. Output that has been ignored in recent years suddenly become hugely popular and Amazon sales rise 700-fold.
It's all a timely confirmation of a recent New Scientist article that discusses the longevity of performers' careers extending beyond their peak. The reason? People are social animals who like/need to share common ground.
The human desire to find common ground in conversation pushes us to discuss already popular people.
The long tail of marketing is not one of low sales across a wide range of products, it's a long tail of continued sales across a wide range of time. Making your marketing interesting now will ensure that it remains interesting long into the future.