This is actually semi-useful. I had a blog thread called "Roads Gallery", and I wanted to show the whole thread on one page for people who click a link from my car page.
I'd like to say I found this by reading the source code, but actually, I just tacked something onto the GET string, and it turns out this works:
Undocumented feature? Beats me. I sure couldn't find it. Anyhow, developers, please make sure you don't break that. ;-)