His blog
post explains a few of the specific problems he encountered while creating it:
"The most basic issue with implementing this is geocoding all of the
location strings (like "Canal & Broadway") to a latitude/longitude pair... It is not
perfect, but since the set of addresses is pretty tightly constrained, I was able to add some
rewriting rules to make the input more easily parsed. As of right now, 54% of the addresses
are geocoded."
"I didn't want to directly scrape the HTML of the site to
extract all of the quotes. I ended up using the data stored in Google
Reader's archive of the site's feed. This allowed me to get at the quotes themselves
more easily, without having to worry about the chrome of the
site."
"Instead of each marker being its own overlay, I put all of them in
the same overlay (see the QuotesOverlay class). Additionally, I did
not split each marker into several layers (shadow, image, click area) - having the shadow be
part of the image works well enough."
