Pin in the map is nothing less (or more) than one-click placemarking, to which you can add text, a picture, an optional password for later editing, and then email the resulting unique URL to friends (example). I’m reviewing it on Ogle Earth because every URL, if appended by “/earth”, will also open in Google Earth.
The business plan: “Premium pins”, minus the Google ads and plus your business name in the URL.
The latest iteration of Microsoft’s Virtual Earth offers something nearly as simple to use as Pin in the map, and its enhanced “collections” feature lets you group placemarks, which I can see even casual users wanting (Pub crawls, photo collections, house hunting candidates…). These collections can be private or public, too. As with Tagzania, however, you first need to log in before you can use Virtual Earth’s placemarking features. And there are no links to Google Earth in Virtual Earth, of course:-).
Pin in the map‘s unique feature, then, is that you need no account to use it, and this will speed adoption by casual users. Having in the past called Tagzania a “del.icio.us for places”, there is no escaping the obvious conclusion that Pin in the map is the TinyURL of places.