No user of OSM OpenStreetMap data has to display the attribution right on top of the map, that just happens to be the most popular style of attribution. The [CC-by-sa][1] demands attribution "in any reasonable manner", and requires that "at a minimum such credit will appear where any other comparable authorship credit appears". A link with an obvious text (such as the "Copyright & License" link on osm.org) satisfies these requirements. [1]: http://creativecommons.org/licenses/by-sa/2.0/legalcode

No user of OSM has to display the attribution right on top of the map, that just happens to be the most popular style of attribution. The [CC-by-sa][1] demands attribution "in any reasonable manner", and requires that "at a minimum such credit will appear where any other comparable authorship credit appears". A link with an obvious text (such as the "Copyright & License" link on osm.org) satisfies these requirements. [1]: http://creativecommons.org/licenses/by-sa/2.0/legalcode