Thanks DiapDealer. I never used Twitter beforehand and haven't checked it all the way.
On the other hand, I don't really care if someone else sees the articles headers I'm marking for further reading... The idea here is not about marking texts inside books... though it will work the same.
About the overall saying that it is way too complicated, well, I think is the way I've described it (too lengthy?), not the way it is working. At the end of the day, the only action I need to do is mark an article header in the Kindle and hit the Alt+Enter and then "Share".
Setting all the above (which is actually only the ifttt if you already have twitter) is a onetime less than 5 min.
On the other hand, maybe I see the things differently
Thank you all for your feedbacks.