Sounds like a buyer tool to me. As a buyer I have seen some sites that put a green dot in the corner of any item the buyer has purchased previously, and an orange one on items the buyer has already viewed before. I see it as similar to Etsy's green dot that let's us know this is a repeat customer. As a buyer, I find it helpful, it stops me wasting time looking at the same items over and over again. It stands to reason that as a seller you would have looked at some of your own listings in the course of your day. If you also use your seller account to purchase, it sounds like the system is just letting you know, as a buyer, that you have seen these listings before.
