I've blogged about it before, but I'm encountering it again while wrapping up issue 36 of Casefile Clues, so I'll mention it in hopes that someone notices.
Ancestry.com's maps indicate a level of precision that simply does not exist in many census records, particularly earlier ones. This is a map showing the 1830 residence of Harlem Township, Delaware County, Ohio.
Every former farmkid (yours truly included) knows a township is not a specific point, but rather generally a square and a fairly large one. In many locations it's a square 6 miles on a side but not always. I just do not like the maps indicating a level of precision that simply does NOT exist in census records this early and doesn't usually exist in census records in rural areas period.
Maybe there just ain't any former farmboys working at Ancestry.com. They'd know a township ain't a spot on a map.