Why do I keep seeing Ebay purchases on my pages? Who cares?

I bought a purse on Ebay. Now, on many of my pages, there are photos of it and photos of other purses of the same designer. What does this accomplish? Who cares ? Who is doing this? If I simply look at something on Overstock there it is on my pages for weeks. Just from looking. I feel like I’m in a goldfish bowl. Who is doing this and for what purpose?