Hi all, say i am selling a product in ebay, amazon and etsy. what if i use the same identical title, description and keywords (product tags) on all 3 sites? will it considered as duplicate by google?
Yes. It will consider a duplicate article if you use the same article on three different sites. But on the same site, you can keep some similarities such as we have products "iPhone 13 battery" and "iPhone 14 battery". So in this case we keep some similarities without the product models. But for different sites, it will be considered a duplicate and Google will be confused about which one to rank.
Google's main concern is duplicate content across the same site. I'd optimize my listings how I thought was best. All three of those sites normally get traffic to the listings internally through their own search feature, not so much from google search.