Adobe researchers have constructed a time machine that lets you view any web page over time, scrolling to see changes in data. But the Zoetrope software ...

The Wayback Machine has been making backups of the world wide web since 1996. Mark Graham, its director, describes it as "a time machine for the web.

When you want to switch Time Machine drives, it's fairly easy to transfer your old backups.

Time Machine is a software that's built into your Mac, and uses an external drive to save versions of your computer, taken hourly everyday.