Site Specific Browsers (SSBs) provide a great solution for your WebApp woes. Using Fluid, you can create SSBs to run each of your favorite WebApps as a separate Cocoa desktop application. Fluid gives any WebApp a home on your Mac OS X desktop complete with Dock icon, standard menu bar, logical separation from your other web browsing activity, and many, many other goodies.
Small OS X window titled 'Fluid' with label 'Convert to Desktop Application', two text fields labeled 'URL' and 'Name' and 'Create' button. The 'URL' text field value is 'facebook.com' and the 'Name' text field value is 'Facebook'.
Fluid includes Tabbed Browsing, built-in Userscripting (aka Greasemonkey), URL pattern matching for browsing whitelists and blacklists, bookmarks, auto-software updates via the Sparkle Update framework, custom SSB icons, a JavaScript API for showing Dock badges, Growl notifications, and Dock menu items, and more.
The Fluid Thumbnail Plug-in allows you to browse the web with CoverFlow or iPhoto-like thumbnail previews for links on the current page. Watch the screencast in the sidebar on the right to see the Thumbnail Plug-in in action. How does the Thumbnail Plug-in know how to find the links on the current page from which to make the thumbnails? Simple... Use CSS selectors to select links or images for a given URL pattern (like *google.com*). Add CoverFlow support for your own site with a simple CSS selector!
http://www.fluidapp.com/
