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As a user, there are certainly times it's helpful to have the browser tab text, especially if I have a few tabs open on a single site and want to distinguish between them quickly. From a search engine's standpoint, I don't see why this wouldn't be one more piece of possibly useful information. However, as you pointed out, if the user happens to have one window open with dozens of tabs, then each individual tab is so skinny which results in only the brand favicon/icon as important.

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Thank you both. Upon further digging in Bing's documentation they do state a 404 or 410 can be used.

Hi, Great question. Normally it is best to use an old sub domain. Said that,  it will depend if it has good inbound links highly thematically related with the new products/content. I think it is not accurate that the url should contain an exact match to the products. It is best if it contains a comprehensive keyword as "a full picture" for products related to "art" in this case. When I face these facts I question myself, when a visitor will arrive, will he find the product/knowledge as I said in the page title and the meta description?. If so, I keep the sub domain and the pages of interest, as well.