Josh, the co-founder of Astria, discusses the journey from data availability layers to building a shared sequencer network. He explains the concept of shared sequencing and its advantages, such as amortizing the cost of engineering and providing a competitive experience for rollup developers. He also addresses the trade-offs and constraints of using a shared sequencer, including the block time and potential lock-in. Josh highlights the target market for shared sequencers and the potential value accrual in a world where multiple rollups tap into the same shared sequencer. Astria is focused on building a shared sequencer for rollups, which allows for faster and more cost-effective transactions. The market is still evaluating the cost and security trade-offs of shared sequencers versus centralized providers. The architecture of a shared sequencer relies on a distributed network, but it remains to be seen if it can be cost-competitive in the market. There is also an ideological question of where to draw the line between a developer building an app-specific rollup on a centralized sequencer and writing to a base layer. The landscape of optimistic rollups versus ZK rollups is constantly evolving, with ZK technology progressing significantly. Base sequencing refers to rollups that are purely dependent on the block producers of the L1, while shared sequencing involves a separate sequencing layer. Astria's go-to-market strategy involves vertically integrating and building their own rollups on top of the shared sequencer to demonstrate its viability.