Ten years ago Netscape released the source code to their browser. They called it Mozilla, I downloaded and built it at my work at the time. I didn't manage to build it immediately, but I worked it out in the end.
Somehow I've spent most of the past seven years working with the platform. I touched on it at Eazel where we used Gecko to display HTML, but mostly left the hard work of integrating a barely-ready gtkmozembed to Mike and Ramiro
Then at Danger I ended up as the main engineer working on our licensed fork of the ProxiWeb web proxy (love those innovative names) which used Mozilla (circa M6 or M8 I think) on Solaris x86 to format web pages for display on hiptops and Sidekicks. Later we built our own web proxy based on Mozilla 1.3, following a similar model but with all the lessons we learned maintaining the old code for years.
Eventually I ran away with the circus as one of the first employees at Flock where we were trying to re-imagine the desktop browser experience, based on Firefox. After a couple of years struggling with vision and execution they worked it out - soon after I left. Now it's showing the potential of moving beyond the dominant Mosaic-with-tabs user experience that the main players are following.
Now I'm at Songbird, building another kind of browser - one whose focus is integrating media consumption and management. We're building on XULRunner, the application platform that has been spun out from the Mozilla applications. It's not my favorite platform for building applications, but how else are you going to build a cross-platform web browser.
Somehow this passing interest I had ten years ago has turned into a career.