Paperback has only been 'live' on Amazon for a day or so but I have sold some. Sold quite a few Kindle versions of my books and stories and less so on the Apple iBookStore.
I'm not doing this to give up my day-job (probably a good thing I'd be eating bread and water right now) but as an outlet of my creative side that doesn't get used during the 8 hours I'm at work.
It's nice to know my work will outlive me though, but that's not too important. Seeing your name on a paperback sold on the worlds biggest bookstore does have quite a nice feel to it though.