I'm an old-time user of Reddit, Quora, Facebook and Twitter and the feature which I miss the most on Steemit right now is notifications. Yep, N O T I F I C A T I O N S.
At the moment, my process of checking if someone commented on my posts looks like that:
1. Click on Profile menu button
2. Click on Blog tab
3. Click a post's link
4. Scroll down to see if there are new comments
This User Experience problem could be easily solved with Notifications. I don't ask much, just:
1. Notify me when someone comments on my post or my comment
2. Notify me when someone mentions me on their posts or comments.
I bet, that Steemit's users activity would skyrocket after implementing this feature. Simply because the core of every successful social network is interaction between people and doing it on Steemit is the hassle at the moment.