OpenStreetMap
I wonder if there's any place that has a list of places to check; I found a road at osm.org/edit?editor=remote&lat=42.14573&lon=-88.0402&zoom=15 that doesn't line up at all with the satellite imagery, and while I was thinking to go and check for myself, I was thinking it would be nice to have a centralized place where people can add a "hey, this might not be right" area.
Абмеркаванне
Камэнтар z-dude ад 17 Кастрычнік 2011 у 02:09
usually, people add a 'fixme' tag to things they think should be fixed in the future. Ie, you add half a trail.
http://keepright.ipax.at shows fixme tags, as well as common mistakes such as errors caused by bad imports.
There are several quality tools out there. osm.wiki/Quality_Assurance
I think there's also a site which highlights 'unmodified tiger import' so people know to check tiger imported data (usually, the nodes don't connect to manually added roads, or are low resolution)
Камэнтар Takuto ад 17 Кастрычнік 2011 у 05:47
http://openstreetbugs.schokokeks.org/ - very useful tool to post "bug" markers. They can be seen after that in JOSM editor, also in Osmand navigation program. Sadly, AFAIK there is no history layer - after bug was closed it stays on map for a week, then dissapears without trace.
Камэнтар tachoknight ад 21 Кастрычнік 2011 у 00:13
Those are great sites; it'd be good if there was some link from OSM to them directly, or put together something equivilant on the OSM site for others to use