I am studying some new emerging p2p protocols, then I found dat protocol.
In dat protocol, if I install dat and use it to share folders, I will become so-called peer and also store other peers's data, right?
I found no docs and FAQs saying that where and who are the so-called peers. Is it right that the PCs in which every users install dat will act as peers who share and store data for each others? and only dat client will do that? any other software?
It's important to know you control what data you download and share.
When you run the Dat CLI, you specify either a URL, or the path of a folder on your computer.
If you give an archive's URL, you will download the files in the archive, and then share those files on the p2p network until you close the CLI tool.
If you give a folder path, you will create a new archive, and Dat will give you a URL to share.
In practice, this is similar to how BitTorrent works. Each archive is a set of files, and so "swarming" an archive (that is, joining the network to exchange it) will only upload and download the files in that archive.
Peers are people who possess the URL, and who have told their Dat clients to swarm the URL. As of yet, there's no Dat client which tries to automatically download more than the URLs given explicitly by the user, but such a thing would be possible.
There are multiple clients for Dat already created:
The dat-node library is written in javascript and is relatively easy to use for creating custom clients.