“If you write a book, the publisher knows how many copies of the book have sold, and they can report that to you. Do they report how many copies were sold to libraries (cache)? Do the libraries report how many times the book has been checked out?”
I don’t see the book metaphor as being as appropriate as Tom seems to.
First, Jeff’s (and your, and my) content isn’t being sold to these “libraries” (Google, MyYahoo, and the rest). Second the public library isn’t making money from the content of the books they buy, whereas your, my, and Jeff’s feed’s are part of the content that creates value for the aggregators like Google and MyYahoo. What’s more, while it might be an unreasonable burden to ask libraries to report on check out counts, especially since many of them have barely made it into the 1990s by now, it’s a trivial request for Google, Yahoo! and the like to add that data to their requests fr a feed’s content. For them not to do so smacks of the walled garden approach to user data, but with users of my content, not theirs.
That said, I tink it’s better to be self-sufficient in this area – there’s no way to guarantee that the Big Fellas will report or report accurately. However, I don’t know of a way to collect that information regarding who’s reading my feeds through their windows. Even my Feedburner feed reports dn’t see how many subscribers I have on some services. If anyone else can enlighten me, I’m all ears.