It's important to start with Bitcoin, and I've found you can get through it quickly and appeal to a broad audience by explaining it as follows.
Bitcoin is two things that have never before existed: hard digital money and mathematical certainty in monetary policy. Censorship resistant value transfer and transparent network operation.
The Federal Reserve controls two main levers of power: interest rate and total supply. Now, imagine if the Fed had a predictable, deflationary schedule for currency issuance and a provable, certain total supply ever possible at some future point in time. Now, imagine the Fed lets anyone that wants to help secure the network do so and they're rewarded. It also decides to become "open source" and thus completely transparent. Everyone becomes their own bank.
Use Bitcoin to set the hook and reel them in for the more lengthy explanation of Steemit.