The social network paying people for their attention is the smart initial move to attract a community.
Then I think the real strength is how elegant and developer-friendly this blockchain is relatively to other ones like Ethereum or EOS.
At first you see the usernames as addresses and the fast 3s blocks.
Then you see how elegant SteemConnect and you realise this is the FacebookConnect you always dreamed of.
Finally you see on Steemd.com how Magicdice and Steem Monsters are interacting with the blockchain. This is when you realise you also want to develop dApps on Steem and become a blockchain developer.