Filename format: archive_YYYY-MM-DD_HH-MM-SS.json (GMT)
Data format: [ [pubkey, title, [latitude, longitude]], ... ]
Script under CC-0 license (public domain)
Warning: please do not blindly rely on this. At some point I'll maybe add per-file compression. (probably bzip2, which compresses one file to ~50%. I could also use tar.bzip2 over longer periods like weeks or months)