Yes, we use it today! libp2p is the P2P Networking Stack of IPFS that we refactored into its own project so that others could take advantage and be part of its ecosystem as well.
It is what gives IPFS and other projects the P2P connectivity, support for multiple platforms (including Browsers) and more! There are 3 implementations interoperable today at different stages of completion (Go, JS for Node.js & Browser and Rust). Full overview here https://www.youtube.com/watch?v=CRe_oDtfRLw
Also, Chris Pacia recently delivered an amazing talk at QCON about libp2p https://www.infoq.com/presentations/blockchain-libp2p, I totally recommend checking it out.
You can find more talks of examples and use cases at https://libp2p.io/media.
Give it a spin and post feedback on github.com/libp2p. We are also on #libp2p on freenode, come say hi!