Here is a look at my Amazon 30-day sales graph as of yesterday
The spikes you see in the first graph directly correlate to paid advertising. There's a little residual sale activity after the ad, but beyond that, crickets in the whole book sales area.
What's notable is the continued page reads after the sale is over. Two weeks after the ad went live for Dying Embers, I'm still seeing people in the KU program reading books even if nobody is buying the whole thing all at once.
Sure, these numbers aren't going to wow anyone and I'm nowhere near making the list of top sellers in KU, but to see residual pages reads at all is always welcome.
This is why I keep my books in KU. As I've said before, the times I've taken my books to a wider distribution, I do not see enough sales to make up for the page reads I've lost. Of course, your mileage may vary. We all have to do things that work best for us. I just don't have a wide enough reach to bother having my books available everywhere. And I don't have a large group of people out there telling me they'd buy my books if only they were available for Nook or Kobo or whatever. (I used to have a couple people who asked, but one sale here or there wasn't making it worth my while. If you don't have a Kindle and want to read my books, Amazon has an app for that.) My stay in Kindle Select could change, but for now, this is working for me.