They replaced it in 2006 with an algorithm that gives approximately-similar results but is significantly faster to compute. The replacement algorithm is the number that's been reported in the toolbar, and what Google claims as PageRank (it even has a similar name, and so Google's claim isn't technically incorrect). Both algorithms are O(N log N) but the replacement has a much smaller constant on the log N factor, because it does away with the need to iterate until the algorithm converges. That's fairly important as the web grew from ~1-10M pages to 150B+.
> That's fairly important as the web grew from ~1-10M pages to 150B+.
This is the weird thing -- it feels smaller. Back in the early 2000s it really felt like I was navigating an ocean of knowledge. But these days it just feels like a couple of lakes.
(also, I'm pretty sure it was billions already quite early on?)