Recently I discovered Fluid, and I fell in love immediately. Its simple interface belies the power this tool provides. Because I rely so heavily on web-based applications, particularly the services Google offers, Fluid provides convenient access to the sites I visit hundreds of times a day.
Fluid, a single site browser generator for Mac OS X, takes a specific website and turns it into a standalone desktop application. With support for Userscripts.org, the applications generated by Fluid can be extensively customized and integrated with existing desktop applications. Particularly useful is Fluid’s support for Growl, which provides notification support for many OS X programs.