If you only check out one website this week, make it Wikimapia. it's a bold combination of google maps and the wikipedia metawiki and it allows you to draw a little box around and start a wiki page/description for absolutely anything you can see on google maps. The interface is pretty damn impressive too... full screen google maps.
If there's one thing I wish this project had it would be an implimentation of tags... anything you tag or edit should become a part of your personal browseable library of places.
I can see this becomeing VERY popular very quikly... and I can also seeing it turning into a catastrophic mess... I'm not so sure it's as people policeable as wikipedia yet... what I think it could use is "place feeds"... RSS feeds on any geographic region from a county, to a city, to suburb or region... so that people can subscribe to a geographic region of interest and keep track of updates and cheanges within that region. That might well clear up the issues in a hurry.
Also... I'm having a hard time trying to find permalinks to specific locations... like the article on the local ice cream parlor. :) The link structure is awesome and updates on the fly, but the specific item descriptions need to be linkable.
Wikimapia - Let's describe the whole Earth!