The steem blockchain is like a database. Different websites can read and write that data. Steemit is just one website that accesses the steem database. The others do that too. So there are ways to add features that steemit has not yet added, on other websites a person could create. As an example of programming code that can access the steem blockchain/database, see http://piston.readthedocs.io/en/develop/lib.html I don't know if you program or not, but anyone can come up with cool new ways to access the blockchain data and make their own websites to present that data, for example by making a site that shows replies and makes a sound or something, whenever a new one comes in.