I use the Kindle application on all three of my devices a LOT. It's used mostly on my iPad, yet there are times when reading on the move using my iPhone can be a real time-filler. There are also times when I need to research on my Macbook, so it's definitely one of those rare apps that, for me, isn't tied to a single device.
I use the heck out of the highlights feature as well. I read a book once and then retain maybe 30% of the information I've read. Rather than re-read the whole book, I'll scan through these highlights instead. This helps cement the information into my brain and frees up the time to move onto another title - and the whole cycle of learning begins again.
One thing that comes to mind with this workflow is the location of these highlights. When you create highlights on any Kindle device, they sync to Amazon's cloud service - however, as with any service that we use, there is always a chance that it won't be around at a time we need it. I'd love to be able to have an 'offline' copy of these highlights that I can then do as I please with, whether this is storing them in a DEVONthink Pro Office database or creating separate plain text files. I just wanted to look at another potential option.
A quick search led me to a bookmarklet stored on Norbauer.com. There is a simple, well-defined set of steps laid out for adding the bookmarklet and downloading the highlights for any book that contains them, within your Amazon Kindle collection.
I won't lay out the steps here, that's a complete waste of time and I'd never make it look as good as the team there have done anyway! So click this link, follow the instructions and look at how you can now work with the highlights in your Kindle books offline!