The Geo Crawler is a free tool.
It can be used as an information source as it creates a tree-like structure using google maps layers.
The visited domains are linked each other, creating a origin → destination relationship between their geographical positions (coordinates).
The results of this process generate interesting graphs of relationships in a world wide map.
Markers shown in the map are the geographical representation of the visited websites during a process. This process is called run.
The information of each visited website is displayer as a Google Maps marker.
These markers placed in the map are clickable, the action reveals an Info Window with the website details:
The Info Window shows the website link, the crawler level and the request number reaching the domain for first time.
Markers are draggable too, so, the lines connecting them will follow the drag effect.
To drag a Marker makes no changes on the run data. Drag action it's quite helpful when markers overlap, and the lines are too close to each other.
Regarding register, your email address is kept in order to save your runs in your profile.
Your email is not shared or used to send any kind of information but the first confimation email with the access password.
The account can be deleted at any time, and there will not be any traces of your email in the system as your data and runs will be deleted without any possible recovery.