When you share 'Publicly' your information will be truly on the world-wide-web, accessible to anyone in the world who has the URL to find it without them having to have a KeepandShare account or otherwise log in and identify themselves.
It's easy to set your information to be 'public'. Just follow these steps:
- Edit the document (or photoblog).
- Choose the 'Public' share group in the Groups pull down in the Share With controls.
- Save your document.
Here is a picture of the Share With controls set to Public:

If you choose to share public you may also choose to allow edit rights - but be careful, if you grant edit rights to the public share group, this means that anyone can edit your shared information, even if they do not have a KeepandShare account.
You can also easily set sharing at the folder level by clicking on 'Share Folder'.