We initially called Go a "systems language," because we wanted to use it to build systems software. What we mean by that is high-performance networked programs that run on multicore machines. The kind of server stuff people traditionally use C or C++ for. Since Go's release last November, we've seen interest in Go from a lot of different places. There was the high-performance computing crowd that we were targeting, but beyond that we saw a lot of users of interpreted languages who craved more speed with the same ease-of-use.

We're yet to see which major niche Go fills, if any. There's a growing community of people from different backgrounds using it, and they seem to enjoy it. I personally think it's a lovely language to write all kinds of code in. I recently rewrote our continuous build client in Go, and I found it a cinch to write it in clear, reliable, maintainable way. It's definitely worth checking Go out because, even though it ticks a lot of the same boxes as existing languages, it's quite different from anything else out there in many subtle ways. Certainly for writing server daemons it totally kicks ass.

It's easy to get started. The standard library is featureful (http://golang.org/pkg/), and there's a lot of good documentation (http://golang.org/doc/docs.html). As for integrating with existing code, Go comes with a tool called cgo (http://golang.org/cmd/cgo/) which allows you to write Go code that links with C code. It's pretty easy to use, and there are many third party libraries (http://godashboard.appspot.com/project) that use it. There's also Go support for SWIG for linking against C++ code.