Not the Apple backup service, but the concept of putting a box full of stuff in the ground.
This seems to be a good example. A capsule left under a church in Oklahoma 100 years ago, chocked full of historical goodness!
Think about it though, if we put a time capsule in the ground today and get everybody to open it up in a hundred years - We're missing the point.
The point it to show the people of the future what it was like to live in your era. It's fun and fascinating. Today though, we're living in an Information Age. We go so far as to document what we eat and upload it.
The reason archeologists are around to dig, is because nobody recorded it. The Bible and Census are the greatest recollection of Jesus that we have today - but what if he had a Facebook page?
"How will people in 200 years know how we lived though?" Surely somebody in 200 years will just Google it, or Bing it even.
We're creating a massive reduction in jobs for Archaeologists of the future, because we're creating the largest bubble of information through media. Our books and our blogs will tell our story.
I'm sure the people of the future will still enjoy funny cat videos too!