Lately, researching nomadic cultures, I've discovered that most of the material available on the web regarding subjects of a nomadic nature are all about travel. While travels or movement is certainly a part of the nomadic experience, travel for the sake of travel is not really what it's all about... that's called being a tourist.
There's always an underlying reason. Seriously, no true nomad ever wanders aimlessly...There's always a purpose.
For most nomadic cultures the underlying reason is almost always economic in one form or another and it's certainly something that folks on boats should take to heart. For instance, some places are cheaper than others and, as such, are good places to provision, Other places are good places to get a temporary job and build up the cruising kitty and so on.
Another reason for movement of the nomadic sort is political... In fact, cruising Europe and environs of late (for American cruisers) has become quite problematic due to the Schengen treaty which makes long stays in most of Europe something of an exercise in creative travel to keep the functionaries happy. Of course, the other side of the coin is sometimes it just makes sense to get out of Dodge when the local Powers-That-Be become unsympathetic or downright antagonistic towards folks on boats.
Then there's the whole where the wind blows thing... Cruising is by its very nature a seasonal pursuit of following the good weather and winds. Face it, you'll never see a nomadic culture going towards worse weather in the winter because it just does not make a lot of sense and, making sense, is really what it's all about.