I read a lot of out of copyright (and sometimes out of print) books, which I download from Gutenberg.org and then transfer from my Mac to my Kindle, usually with the excellent Calibre app. I just connected my Kindle to my Mac with a regular micro USB cable, and while the Kindle charged okay it didn't show up as a storage device on my Mac and Calibre didn't recognise it, either.
I then tried another micro USB cable, and that didn't connect the Kindle as a storage device, either (it charged it, though, just like before). Finally, I dug out the micro USB cable that shipped with my Kindle and this one worked: my Mac recognised my Kindle as a storage device, and Calibre was able to send books to my Kindle.
So, should any micro USB cable work fully with my Kindle (i.e., connects it to my Mac as a storage device, as well as charging it)? If not, what's special about the cable that shipped with my Kindle?