The new and improved sharing / social feature in Instapaper is great. Before 3.0 you had to know someone’s exact Instapaper username and then subscribe to their “favorites” folder. And since Instapaper recently began requiring people to have email addresses as their username I’ve been hesitant to share mine publicly.
But now to subscribe to the articles someone likes in Instapaper you can find them much more easily if you also follow them on Twitter, Facebook, etc. (Though you will only be able find them if they have hooked their Instapaper account to their Twitter and/or Facebook accounts, etc.)
You can find my Instapaper likes via my Twitter account. I’m @shawnblanc on Twitter and if you follow me there, when you log into Twitter via Instapaper you’ll find me.