2600 and counting

I've always said I won't give my books away for free, unless they are for reviewers or some hand-picked people I want to give the books to.
Now I have been hearing good things about the Amazon KPD select programme -- something to get your books out there, your face and your writing known. Let me explain in short: you are exclusive with Amazon for 90 days in which you are  not allowed to sell e-copies of the enrolled book elsewhere. During that time you are allowed (you don't have to) give away your book for free for five days. You can do them all in one go or split them.
I've enrolled Excuse me, where is the exit? and also my new book Candlelight Sinner, which I both unpublished and removed from Smashwords since I never really made money there. Amazon is my main sales outlet.
Now my sales weren't too bad, but not very good either. Roughly about 150 in the past months, slowly going up again, but that's not enough to rectify the hard work I put into writing and promoting them.
With the promotion -- both books are free over the weekend -- I had over 2700 downloads since yesterday. To be honest I'm still in shock about the vast amount of downloads. It seems that my short stories do really well in the humour genre (position 3 as I type), yes even in the overall free charts (position 19). Candlelight Sinner has taken off on Amazon.com.
I wonder if that mirrors the 'buying' patterns of readers. I will admit that downloading freebies is addictive as I have downloaded about 20 books myself in the past two days. I only downloaded what I would buy in a shop, based on the pitch and I know I will give all of them a try, hopefully finding one or the other gem.

But with books on promotion for free on a daily basis, I'm a little worried that readers might rather download free books than paying for them, especially if they are by new Indie authors.
Many authors who have enrolled their books have reported an improvement on sales and it better when I think of the amounts of books given away. I expected only a couple of hundred downloads, but the actual figures make this one author dizzy. By the way, since starting this post about fifteen minutes ago, I had another 100 downloads. If only that would happen every day, with readers paying for the books. :-)