The success of the STEEM blockchain is the flexibility it provides for other applications. Steemit is definitely the main gateway and with the upcoming hives update, it will become a more direct competitor with Reddit. Many other platforms are also being built to be direct competitors to other well known platform. For example, Zappl is like Twitter and Dtube/Dlive are like YouTube. There are others coming as well. This has not brought issues of scaling yet as per Blocktivity, STEEM continues to be the best in its class with transactions and bandwidth. Lastly, the coming start of SMTs could also bring the potential of more mainstream content providers as they look to monetize their content. The potential is definitely there given the ecosystem the blockchain is supporting.