When active, it sits in the sidebar of a web browser. It looks like this:
I have been playing with the service this morning, and I am not completely sure that this service is still in operation. But since I got it from a list of working GR alternatives, I'm going to assume that it is.
This is an interesting idea, but I don't think I will use it. Just the sight of the sidebar sitting there, taking up screen real estate, annoys me. It sits there contributing very little while offering a visual distraction.
But never mind the visual annoyance; I would pass on this service because it offers a constant distraction from my work, and that's not conducive to getting work done. I don't even pay this much attention to Twitter any more, not while working, and I don't see a reason to add a permanent on screen distraction.
And given the current state of web browser design, I don't think there is a need to give up screen real estate. You can now easily keep all the linked web pages open in tabs and switch to them throughout the day.
But in spite of all my reservations, I'm sure this service is going to fill a few niche use cases. It is certainly not like any service I have used before.