Bill Gates retired Friday from his everyday duties at Microsoft, leaving behind a company which managed to sell billions of copies of software over the years. The once-most-wealthy-man-on-Earth will dedicate most of his time to the wealthiest charity in the world: the Bill and Melinda Gates Foundation.

William Henry Gates III, 52, will thus apply his business genius to a charity which enjoys a $34.6 billion endowment, organized three departments: Global Health Program, Global Development Program and United States Program. Bill Gates is co-founder and co-chair, as is his wife Melinda French Gates. William H. Gates, Sr., who is Bill's dad, is co-chair and Patty Stonesifer is the charity's CEO through the end of the year, when responsibilities will be taken over by former president of Microsoft Corporation Jeff Raikes.

Gates will still go by Microsoft's headquarters once a week to check up on the company, where we will remain Chairman for the foreseeable future. Meanwhile, Steve Ballmer, Craig Mundie and Ray Ozzie will have more independence in running the world's largest software company.

What will happen next, will Microsoft be slowly crushed by its own weight? Will Microsoft be able to catch up on Google in the advertising and search markets? What will happen to its flagship Windows operating system, whose sales declined with Windows Vista?

One thing is certain, though: Bill Gates helped shape American economy and especially the IT sector in a major way over the last decades, and his legacy, with its ups and downs, is here to stay for the foreseeable future.