Under Places > Migrations is a map that compiles statistics for how many people moved from or to a selected place. This covers all families entered on the website. You select a state or country, plus a county or province, but a city or town (or cemetery) is optional.
If "from" is selected, it compiles the data for all people who were in the selected place, and then moved to another place. If "to" is selected, it compiles the data for all places where people lived, and then moved to the selected place at some point later in their lives. Selecting a cemetery only applies if you select "to", as most people don't move from a cemetery once they get there.
Above is a sample showing all people who migrated from Washington DC to other places.
Colored lines willl radiate out from the selected place, linking to all the other places where the people were from, or migrated to. The color of the lines, and color of the pins at the endpoints correspond to the number of people who migrated between those two places.
Clicking a pin at an endpoint will show the name of the place, and a link to the page for that place.
As with any Google map, use the + and -- buttons on the left to zoom in and out, to a better view of the places.
Note that this is limited to only events that have dates defined (except for "grave" events, which can be assumed), and only places that have been identified with latitude and longitude coordinates -- another reason it's always important to fill in dates where possible, and to be consistent with place names so that they can be mapped.