I had the idea about 5 years back that it would be nice to share via the browser any kind of content with one's primary email contacts list. There could even be shortcuts or predictive text (like in Gmail when you start to enter someone's email address). Think of it like a box, much like the search box in Safari's top right corner where you could select 'article', 'video', etc from a dropdown and then start typing the email you wish, click send and violá.

Perhaps this already exists in some form. Perhaps a Pocket for your friends where you put things on a secondary reading list of theirs so as not to get confused with their own list.