bloglines is entirely C++. I remember seeing some interview where the guy said it was critical to beating their competitors. They were all busy trying to scale while bloglines already worked.
Interesting. That seems to be the exact opposite of pg's view that Lisp was one of Viaweb's main competitive advantages, because it allowed them to rapidly add new features.
I think Lisp is reasonably fast, possibly as fast as C++.
and where are they now
Well, I think the only major competitor to Bloglines these days is Google Reader which is in... C++ as well. Well, I would guess also probably a few bits of Python in between. Any googlers here? :)