Adrian at Cre8asite posted a thread summarizing some of those stats;
In Bloglines they have a pretty decent 1.3 million feeds with at least subscriber. I guess that says as much about Bloglines popularity as much anything, it owuld be interesting to compare that with similar stats from other RSS Reader services. But considering how many blogs there are meant to be, let alone all the other types of site now using feeds for news and things, that seems a relatively low number. And Jim says in the post, they kind of thought, is that all?
And then to show that less than 40,000 feeds had more than 20 subscribers shows the drop off in usage. That's less than 3% of the feeds with at least 1 subscriber also having more than 20.
I also thought the 'Search Index' section was quite interesting. Despite having billions of indexed pages, 6million cover half of all clicked on results. And looking at the graph, 250million cover 90%.
Makes for some good RSS/Blog/Bloglines discussion.