Can I send different Thank You Notes for different products?
No. Thank You Notes are like storefronts in that each creator is allowed only one per account. If you enable your Thank You Note, the same note will be sent to the buyers of all your content, even the content marked Direct Access. If you have diverse content available for sale in a single account (for example, a software manual, a coloring book, and a family calendar) the same Thank You Note will be sent upon purchase of each item. If this is your situation, consider writing a very general Thank You Note message.