Apple released a new Safari update today with Safari 5.0.1.
Safari 5.0.1 is turning on Safari Extensions and introducing the Safari Extensions Gallery.
With Safari Extensions Gallery, users can quickly find extensions that add powerful new features to Safari, from toolbars that display live web feeds to sophisticated programs that filter web content. Safari 5.0.1 allows users to download and install extensions either from the Safari Extensions Gallery or directly from a developer's site.
The Safari Extensions Gallery is accessible from the Safari menu or at extensions.apple.com.