1) It provides an automatic hook to make people pay attention to you. This is the Purple Cow factor -- its so different than what people expect that it is remarkable in and of itself. I am convinced that a lot of the reason people read my blog in the early days, prior to me having any reputation for saying worthwhile things or writing in an engaging manner, was that "real public sales numbers" were as rare as hen's teeth in the industry.

The kind of people paying attention to your are typically folks in your industry, who are very connected, have blogs and Twitter accounts, link to things they find interesting, do I have to paint you a picture?

2) It costs you nothing. What is the worst that can happen, somebody tries to Xerox your business and outcompete you by being you-er than you are?

3) You know how pg advises people to have a co-founder so they won't feel all alone in the world in the long, long slog that is running a business? Many of us cofounderless wretches have an intense urge coming from the monkey portion of our brains to show off what we've been doing (and I don't mean that in the pejorative sense). What is the point of spending 12 hours over a hot interpreter to solve a one-line bug if you can't lament about it to your buddies? Similarly, when you get the sense of elation at e.g. having two whole customers in one day, you want to share that with somebody, too. Preferably, somebody who understands -- and nobody understands these things better than your peers. (Friends, family, priests, and romantic interests are wonderful things to have in your life, but there is a distinct limit to their tolerance for "Guess what? Guess what? I got X uniques today due to my ongoing SEO efforts!")

I don't see this stats page mentioned on their front page nor their blog's first page.

I don't think it'll work as well, since they have a different business model.