Fresh off the heels of launching a slew of yesterday, Apple this morning debuted , switching the flip on Safari Extensions and formally introducing the Safari Extensions Gallery, a directory of available extensions across categories.

The company had introduced extensions support in Safari 5 . Users can download and install extensions from the gallery with a single click, and there’s no need to restart the browser (much like Google Chrome, and unlike Firefox).

I did a quick count and came out at above one hundred extensions already.

Add-ons can be automatically updated and are managed within Safari. Users can enable or disable individual extensions, or turn off all extensions with one click.

Every Safari Extension comes signed with a digital certificate from Apple to “prevent tampering” and to verify that updates to the extension are from the original developer. Safari Extensions are also sandboxed, which prevents them from accessing information on a user’s system or communicate with websites aside from those specified by the developer.

As Apple had made clear earlier, Safari Extensions run solely in the browser.