Metadata is data about data. It can give you additional information about the data you share with others.
Common types of metadata include:
- information about photos (GPS, ISO, photo-editing tools used, etc)
- track changes
- notes for speakers
- name of your computer
- comments
- ...and more
Being aware of what you are sharing (and removing information that others don't need) is an important part of working and interacting with others online.