Complete Question: “How about duplicate content for resellers where the manufacturer or producer of a product describes a product with technical details and so on. Do I have to rewrite text, create my own descriptions? Or is Google able to recognize that i have to use the original text from the manufacturer and not to punish me?”
Answer: Google has a powerful algorithm that may be able to determine “right” or “wrong” duplicate content. That said, I would not rely on it. In this scenario I would rewrite the product descriptions wherever possible and improve the optimization of each description while I was at it. After all, many default descriptions are boring and less than ideal for rankings anyway.
But allow me to remind you of one thing… If you are talking about a shopping cart system where you have thousands of widgets and they all appear using similar text then DO NOT be overly concerned about this duplicate content; it is not a threat to your rankings. Yes it is usually ideal to have unique content but in this case just concern yourself with balancing this duplicate content with added value within the rest of the site. You can do this by adding unique pages dedicated to each widget. These pages can be created whatever unique content you want (diagrams, specs, reviews, etc.) but they ultimately serve to introduce a particular widget to users (and search engines) while providing direct links to the appropriate section of the cart.