Hanging on to user preferences and data

Jakob Nielsen's latest alertbox makes a few interesting points discussing The Slow Tail: Time Lag Between Visiting and Buying.
Important issues from a developmental point of view:

• Set longer expiry dates on cookies used to track visitors


• Hang on to preferences, shopping basket contents, wish-lists etc


• Don't delete landing pages designed for specific campaigns

The number of people who don't buy on that initial visit, but still convert later is really surprising. It might be a good idea to give people who choose not to purchase other options - bookmark this page, sign up for a mailing list, or some other way to help them remember to come back to you.