Seems js-ipfs[0] is not quite ready for prime time (though it's close) and the author had a requirement to do everything from a browser.
Bittorrent DHT doesn't actually run in the browser yet either [2], so WebTorrent in the browser currently only has access to the tracker infrastructure, and thus isn't as decentralized as one might think.
We've been working hard to get js-ipfs to a working level and just last week announced it's ready. While it's still early days and we have plenty to do to make it even more robust, we have it fully working with WebRTC support as of today.
We've developed some apps and demos that essentially enable you to create dynamic content and apps on IPFS, purely in the browser. We do have to currently rely on a centralized Pubsub (in a similar fashion to torrent trackers) but we're working on to provide a decentralized pubsub mechanisms as part of IPFS.
Regarding persistency: js-ipfs and the main ipfs (native go-ipfs) networks are not yet connected but we're very close to having that. Once they all communicate in the same network, we can provide a lot better persistency as users don't have to keep the tabs open in the browser.
Take a look at some of the examples of what can be done today with js-ipfs, that is fully in the browser:
https://github.com/haadcode/orbit (specifically https://github.com/haadcode/orbit/tree/js-ipfs)
https://github.com/ipfs/paperhub
IPFS supports today WebRTC, TCP, uTP and WebSockets, thanks to the multi transport approach libp2p[0] offers. In fact, that is how Orbit works, a chat app build completely in JS, using IPFS, on the browser without any plugins. Check:
- http://orbit.libp2p.io/ - https://github.com/haadcode/orbit
The js-ipfs DHT is underdevelopment, in fact, we have an implementation, but it is not compatible with go-ipfs so we are not rolling it out, yet.
To check the latest updates on the project and learn whats next, check our log https://github.com/ipfs/js-ipfs/issues/30#issuecomment-22604...
[0] - libp2p is the network stack of IPFS, also a standalone project https://github.com/ipfs/specs/tree/master/libp2p
There is actually another one called "Azureus DHT" which came first [2]. It's another big hashtable in the sky, and the Azureus/Vuze clients can connect to either DHT. All other clients only use the second one, the "Mainline DHT", which was an official extension to the protocol [3].
[1] https://en.wikipedia.org/wiki/Distributed_hash_table [2] http://www.bittorrent.org/beps/bep_0005.html [3] https://wiki.vuze.com/w/Distributed_hash_table