The co-founder of Flickr and Hunch, Caterina Fake, is the founder of a new web startup that sounds pretty exciting. It?s called Pinwheel, and it allows you to find and leave public or private notes around the world, and follow sets of notes.

On her blog, Caterina compares the service to Flickr for places, but with notes instead of photographs, ?Is it like Flickr for places? Ish. Part of why making Pinwheel is so fun, is so exploding with possibility, is that a note, like a photo, can be a container for all kinds of things. It is the perfect social object.? To give an idea of what the platform looks like, there is a sample note on her blog of a note that she has left in Grand Central Station, shown below:

Caterina anticipates that Pinwheel will make money from sponsored notes from businesses, that will be available for everyone to see. It will be interesting to see how the start up fares, it?s a clever idea that combines the practicality of map technology with the fun of social sharing, and the mobile aspect is where it?s likely to become more popular, it could prove useful especially while travelling. You can sign up for the private beta version for mobiles and on the web, while there?s an iOS version on the way.