After 10 years at Amazon, I have left to start my own ventures. One of the side gigs a friend and I built several years ago was called Wish List Alerts. After getting a working prototype and getting to over 100 lists we were monitoring, we shut it down. Several reasons for this:
Looking back, I wish we would have hired a free lancer to help keep it going, dug deeper into what we needed to do to get approved for Amazon associates, and made incremental improvements with time permitting, even if it was for learning only. We had received really great feedback (e.g. "I loved those alerts, I used them to buy everything for Christmas."). Oh well, water under the bridge.
Now, I am pursuing my own ventures full time and decided to brush this off and make a go at it again. I will be using Keepa for my data, which takes a huge load off the data needs. I will also be using our family blog to get approval for associates: https://alittlefamilyfun.com/. In fact, I could see this growing to be a service for bloggers and influencers, like a WordPress plugin where they can have their followers subscribe to a list of items they recommend.