The line between the dots (if you zoom in) : GPS track of the way we took.
The dots on the map are places where we stopped or where we plan to stop :
Green dots : Someone else found it for us (we’re assisted people)
Blue dots : Found by Internet (we’re geek people)
Purple dots : Hospitality of the locals (we’re friendly people)
Pink dots : Camp Site (we’re wild people)
Grey dots : We slept on a train/boat/bus (we’re lazy people)
Pour la version française, voir ici.