The ribbon in Office 2007 is clearly influenced by tab-based global navigation used in web sites—complete with the concept of “Home.”
From: Barnes & Noble
From: Excel 2007
Not surprisingly, the idea of a ribbon (essentially, a horizontally-oriented menu) is now showing up in web applications. Smartsheet, a web-based collaborative spreadsheet, uses a ribbon-like approach for its menu of commands.
I think we will see more merging of conventions between desktop and the web as the distinction between these two environments becomes less and less relevant.