This may be a futile exercise. It often seems futile with Amazon, where there's more to see and evaluate, but I have the same question as others asked in another thread, but re: GP, to with: what's changed?
Without any particular promos or changes in the way I do business, my (four-figure) income from GP ebooks more than doubled within the space of two months, and has held steady for the past two months. In other words, if my income (numbers are examples only) I made $3000 in June, in July I made $4500 and then August and September I made $6000. That's a large difference, and with the volume of books I sell, it's not just a blip from one book club buying my books all of a sudden.
Has Google done anything to promote GP books better? Is there any way to see if GP is doing any sort of in-house promos?
Or is it just another one of those mysterious random happenings that there's simply not enough visibility and transparency to explain?