Yea, it's a completely different use case. Internally Google has something called Maglev which looks a little more like Seesaw but even still its quite different.

I haven't actually seen anything like GSLB anywhere else. With classic load balancing we've always been taught to proxy traffic through a single point of entry. GSLB flips that on its head and rather provides routing information which clients can then use for the next set of requests. I'm attempting to develop something similar within https://github.com/micro but it's going to be a long time before I even get marginally close to something as powerful as Google has.