The Arweave network is like Bitcoin, but for data: A permanent and decentralized web inside an open ledger.
Permanent storage has many applications: from the preservation of humanity's most important data, to the hosting of truly decentralized and provably neutral web apps.
The Arweave protocol is stable, mature and widely adopted. As such, its ecosystem is fully decentralized.
The goals and responsibilities of the Foundation are numerous: to maintain core Sia protocols and consensus code; to support developers building on top of Sia and its protocols; to promote Sia and facilitate partnerships in other spheres and communities; to ensure that users can easily acquire and safely store siacoins; to develop network scalability solutions; to implement hardforks and lead the community through them; and much more. In a broader sense, its mission is to commoditize data storage, making it cheap, ubiquitous, and accessible to all, without compromising privacy or performance.