This website provides a web-based index for plugins for Google’s 3D-modeling software SketchUp. It was created with the idea to serve as a community-driven portal where users can find plugins easily, rate them and discuss them. There is also a small plugin that lets you browse this site directly from within SketchUp. All of this is possible without registration.
In addition, any user can contribute plugins (including various metadata), blog posts and forum discussions. Simply register using the small form on the right side and you are set to go!
More information is on the About page. At this point, this site is in Beta-mode, so go ahead and provide feedback in the forum.