Just to confirm, are you looking to set up an affiliate marketplace on your store using Shopify? If so, we do have an Affiliate Marketing app in our app store which might be of use to you, called Affiliate by AAAecmmerce.
You also mentioned keyword searches in your question above. Similar to affiliate marketing, it might be worth taking a look through some of our SEO apps in the app store by clicking here to find one which might suit your needs. We also have a helpful guide that goes through all things SEO/Keyword search related on Shopify here.
Hope these help, but if it is something different you are looking for, could you elaborate a little more and go into more detail of what exactly you're looking for? I would be happy to take a further look for you.
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