What Twitter is missing
These are some features that, while possible in third-party applications, I believe should be integrated into the main Twitter product.
Sure, the favorite button does the trick, but I want my “favorites” to only be my favorite tweets. Instead, my “favorites” often turn out to be tweets I want to go back to when I’m on my laptop. A simple “read later” button that allowed me to create a queue of tweets to get back to would be an incredible value add for many power users. I don’t think this action should appear on the interaction tab for users.