Figures.

Great blog.
Long time listener, first time caller

I think even the way that getting a handle on “subscriber” stats is a bit of a black art.

Certainly, the way that Feedburner describes it makes it sound like they use some sort of proprietary formula — err, algorithm, perhaps — that takes into account a number of factors. Because its proprietary no one knows how they crunch those factors and how they weigh them differently.

To wit:
Subscribers is inferred from an analysis of the many different feed readers and aggregators that retrieve this feed daily. Subscribers is not computed for browsers and bots that access your feed. Subscribers is calculated by matching IP address and feed reader combinations, and then using our detailed understanding of the multitude of readers and aggregators and bots on the market to make additional inferences.

Regardless, the % of people using RSS feeds is, I think astonishingly low for how useful a tool they are; perhaps with the full release of MSIE7 there will be better penetration for it.

Cheers
Tony