I'm also interested in hearing of any completely dynamic sites on IPFS; I'm looking at how I might build one myself. I've been asking in the OrbitDB chat for advice on their planned architecture for replication, but to date there's limited tooling for that.
If filecoin will incentivise people to store the data behind an IPFS hash, there also needs to be a way to encourage people to replicate OrbitDB's pubsub publish events, or (if using IPNS) for to republish 's IPNS records in a trustworthy manner while is offline.
Without a sustainable way of having a node's mutable data be available to others while it is offline/unreachable the dynamic apps that we're used to using aren't really viable. How many distributed-twitter followers would you need following/replicating your tweet DB before it would be available at all times of day if your phone is off? Unless there's a filecoin way of offering a small sum to pay for that replication it's that or ask every user to have an always-on server to keep their "distributed" replica.