A tangent: I allow G+ to auto-upload the pictures and short videos that I take with my Droid. Since I spend a little time deleting all but my favorite pictures and videos, this will eventually be a good private timeline (private because auto-uploaded material is not public until you share it).

If someone spent a few minutes a day also annotating pictures and videos then this would be a good resource for remembering the past.

Hopefully Google Takeout exporting facility will soon also provide download ZIPs for auto-upload materials.