Caterina Fake, co-founder of Flickr and Hunch, has just taken the wraps off Pinwheel, a new social service that already has early adopters buzzing.

Pinwheel is a location-based service that's all about allowing users to "find and leave notes around the world." You can create a note— containing text, images or both— and then peg it to a real world location for other people to see and discover.

Notes can be private, or visible to a few friends or visible to the entire world. Potentially people could use the service to preserve memories, share important information about a place, or send location-sensitive reminders. You can follow other people on Pinwheel to see what notes they're putting out in the world, and tag your notes so that they're easily searchable by keyword.

Currently Pinwheel is in private-only beta. For an invite to try out the service, go here.

[Caterina Fake via SAI]