Finding A Private Blog

Here's something odd. Melissa and I have a private blog that we only mention to friends and family. In Blogger's settings, I've said to not list it on blogger.com or ping services such as Technorati. It's not a restricted blog, since we didn't want to force people to create Blogger accounts, but as far as I know, there's no published mention of the site.

I maintain a feed of sites that link to my public blogs. This morning, I was surprised to find a link from our private blog pointing to one of mine. The link is there, but I can't figure out how the service managed to find it. We deliberately don't link out of the private blog to blogs that might see the traffic. (I don't see any links into it, either.)

Is Blogger's view of privacy different than mine?