This script exports the captions from all .jpg files found the directory it is in and all it's subdirectories (recursive) in a text file per directory.

How to use it:

1. Install exiftool, as described here: Exiftool
2. Download the file ExportCaptionsPerDirectory.bat_txt from the attachements below in this page, and put it in the directory from where you want the tool to start putting the metadata files per directory. 
3. Rename the file so the extension is only .bat instead of .bat_txt (uploading .bat files isn't allowed on sites.google.com)
4. Doubleclick the .bat file