One seems to be a lot more useful than the next. PlaceOpedia exists as a way for users to manually link places on a Google Map with Wikipedia articles about those places. Not to be negative, but isn’t this a task ripe for automation? That’s how the Germans did it two months ago.
Your History Here makes a lot more sense, because here the user gets to generate her own personal historical recollections about a place, which turns the site into a unique living historical trove. That’s a great idea.
(And finally — posting will be a sporadic over the entire next week, as I am off to Paris and then London, where I am about to become an uncle. As they say in Sweden, jag kommer att f√ï vuxenpo√ßng.)