Project Maelstrom is described as 'torrent-based distributed web browser developed by BitTorrent, Inc' and is an app in the File Sharing category. There are more than 10 alternatives to Project Maelstrom for a variety of platforms, including Linux, Mac, Windows, BSD and Online / Web-based. The best alternative is Tor, which is both free and Open Source. Other great apps like Project Maelstrom are IPFS (Free, Open Source), ZeroNet (Free, Open Source), Freenet (Free, Open Source) and I2P (Free, Open Source).
Tor is free software and an open network that helps you defend against traffic analysis, a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security.
IPFS is a global, versioned, peer-to-peer filesystem. It combines good ideas from Git, BitTorrent, Kademlia, SFS, and the web. It is like a single bittorrent swarm, exchanging git objects. IPFS provides an interface as simple as the HTTP web, but with permanence built in.
GNUnet is a framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services. A first service implemented on top of the networking layer allows anonymous censorship-resistant file-sharing.
Sia is a new decentralized cloud storage platform aimed at giving users control of their data. Data is split into hundreds of erasure coded pieces and encrypted locally, and then each piece is uploaded to a separate host.