OK, so you got the free Kindle app on your PC. Trouble is, you read something that you find helpful and want to clip it for future reference. Can you do so? No.
Except you can. If you're also using Evernote (and who wouldn't be?), you simply press the PrintScreen button on your keyboard, then highlight the Kindle text you've just fallen in love with and - voila! - you have the text sitting in Evernote (as an image).
Apparently (I haven't tried this yet), if you have the Kindle iPhone app you can highlight text natively and add your own notes, which are then saved to an Amazon page for you. Then, you'd simply clip from that page into Evernote (using the normal clipping tool, not the PrintScreen one).
Neat!
(HT: Tony Steward et al)