We just added a tiny sharing sidebar to each wiki. This should make it even easier to share your wiki with friends, colleagues, and anyone else that you want to start collaborating with on your wiki. The sharing sidebar is located beneath the normal sidebar, or, if you have one of the tabbed sidebars, it should appear at the bottom of the Quickstart tab.
Depending on your level of security, you will be given the option to share just a regular link to let others read your wiki, or, another link that will give them full access edit pages, and more. Those who have paid for advanced permissions will have greater control, too. Use these links in e-mail, blogs, chat conversations, tattoo it to your elbow, etc.
The sharing sidebar can be turned off in the admin panel (click “Wiki settings” on the bottom of your wiki).