As well as the huge new US base map database for Google Maps (released today) Google have added a link in the bottom right of the map to make it easier to 'report a problem' with the map data. It is also possible to right click on the map and select the 'report a problem' option.
Here is the official YouTube video introducing the new links,
The new links only appear in certain locations. Google also seem to have ended its partnership with TeleAtlas for US map tiles. It could be possible that the 'report a problem' links only appear where TeleAtlas is no longer involved in providing map data.
Hat-tip to Mapperz