My company is a pretty large brand in our niche. We private label our products and have become the largest retailer in the country for our niche. Our website has always had a shopping cart. It always ranked pretty well, but over the past couple years it has since moved off the first page. There are a number of issues that can make this occur, but we are of the belief that websites without shopping carts are now performing better in the search results than websites with shopping carts (I'm not looking for a debate on this). Therefore, we are now building a website that more resembles a brand/manufacturer without a shopping cart.
Here's where it gets tricky. We still want to use PPC to push traffic to our old site with a cart and keep that going through the launch of our new website that we want to rank well. There is obviously a lot of similar content. In fact, product descriptions have simply been copied over at this point. We have basically given up on the old site with a cart ever ranking well again, which is the point in creating a new one.
I'm looking for potential technical/SEO issues and solutions. Duplicate content is the main issue I'm looking to deal with. Is there a tag or something we can put on the old website that says the new website is the authority/original creator of the content? We want this new website to rank.
We're not going to redirect the old site to the new one.
Thanks in advance. Looking forward to any and everyone's input.