I've spent a lot of time creating a Google Earth presentation of my cruising aboard the BlueJacket, which is a 40 foot Freedom sailboat. This includes locations from Maine to Florida and virtually all of the Caribbean. The placemarks include text snippets from the logs and then link to the entire log as well as photos from the area. The logs from most of the US east coast and eastern Caribbean are pretty thin, but the photos are good. Everything gets much better starting in Venezuela and west of that.
Anchorage placemarks utilize anchor icons, placemarks which include diving information have dive flag icons, and land based travel utilize either sign posts, Myan pyramids or airplanes. Icons are grouped by region / country / state or year.