Bill Gates leaves Microsoft. Sort of.

Slight change of plans tonight. Normal posting - including photos, insights on an eventful week in our kids' lives, and a quick look at my evolving media whoredom - returns early tomorrow.

For now, however, the geek in me couldn't not mention that today was Bill Gates's last day as a full-time Microsoftie. As you've likely heard, he's retiring from the pioneering software company that he founded a generation ago to devote more time to the Bill & Melinda Gates Foundation.

He's not going away completely, mind you. Like a genial ex-honcho who just can't stay away, he'll grace his office at Microsoft one day per week, sharing his insights with the folks who will ultimately determine whether Microsoft survives and thrives in the new online economy.

I don't wish to make this sound bigger than it is. People retire all the time. And when they do, life goes on for them and for those they leave behind. Despite his wealth and influence, Bill Gates is hardly different.

Still, I can't help but feel that an era is ending. We've all used Microsoft's products, and we've all witnessed - and experienced - the firm's extreme influence on the PC market's evolution from hobbyist nerdfest in the mid-70s to the economic/societal pillar that it is today.

I've been privileged to have seen him speak in-person three times in recent years. In each case, you could hear a pin drop in a room filled with thousands of people. You could feel how excited he was by the technology he oversaw. You could see the visionary at work as he walked through a scenario for the audience.

His genius was understanding the potential of technology and its ability to evolve our lives, to improve our situation. This genius will now be applied full-time to resolving issues more fundamental than Windows Vista stability: namely, poverty, AIDS, education.

It's been a neat ride so far, and love him or hate him, no one denies that he didn't change the world. As he leaves, I wonder who out there will have the courage to fill his outsized shoes.

Your turn: What makes an icon?