I am pretty sure I have posted a link before somewhere to The World as a Blog. But reading this post again and thinking in linear fashion this time, I remembered seeing the map linked above.
I think it would be cool (at least momentarily) to take geo meta data from the favorites in one's blogroll list and use it with a map like 'The World as a Blog'. I think the connections would look very magical.
It might be more visually satisfying, and a better representation of the romance and imagination of the post that triggered the thought, if it were only points of light on the map, rather than as excerpts of blog posts or if there were some way to toggle between the two. edit: It doesn't always show posts and there is a way to "log in" and see who is looking at the map... and it can be looked at as 'points of light'.
Along the same vein one can generate a representation for "neighborhood" at here. It is not as visually pleasing to me as the thought of all those points of light on the map in Andy's imagination.
But all of the connection thoughts take me to all sorts of tangents.
Edited 6:04PM: Actually the various things one can do with Touchgraph looking at neighborhoods, expanding and contracting some of the nodes is fairly interesting with lots of potential practical applications, unlike my suggestion which has no practical application at all.