Google LatLong Blog reports that Google Maps added a new community layer for the My Maps feature: comments and ratings. That means you can create personalized maps, transform them into wikis, import content from KML files and search results, add photos and videos, embed the map into your site. Even though these community maps are included in search results, I think they're hardly noticeable unless a popular site links to them or embeds them. Ratings and statistics will help Google create charts and show things like "popular community maps in your area" or maybe connect your search profile with some maps.
Maybe Google should also create a default community map anyone can edit. This way, you'll be able to add placemarks directly on the main map without having to create a personalized map.