Update: Oct. 13.
A reminder, I don't take credit cards. If anyone purchases books from me directly, I don't save the purchaser information anywhere. (I do have address and phone info for non-commercial personal contacts in "private" harddrive files that are non online -- but they are saved in the Cloud; I wonder if that could present any real hazard.)
Book self-publishing services seem to assume that many authors will take credit cards individually, at fairs or kiosks, or on their own websites, since they try to sell large numbers of hardcopies to authors. Because of recent security lapses in the news at large companies, running your own credit card operation seems to have become increasingly risky, something that might well be uninsurable. It seems as though the self-publishing companies are unaware of the risk; or at least the people that would call me repeatedly (as in 2012) were unaware.
Nevertheless, a few self-published authors (and filmmakers or musicians directly selling their own DVD's or CD's) do take cards, or at least don't put their stuff on Amazon. As a customer, I find using Amazon much easier, and safer.
Update: Oct. 14
Update: July 20, 2015
Kindle for the first two books is restored.
Note that all my contact with individual buyers is "informal". If you go through me, rather than an e-commerce site, I handle it manually. No purchaser information is kept (so it can't be hacked later).