One in every 600 websites has .git exposed
One prominent human rights groups exposed every single person who had signed up to a gay rights campaign (including their home address and email addresses) in a CSV file in their Git repository, publicly downloadable from their website. One company that sold digital reports provided its entire database of reports free of charge to anyone who wanted to download their .git folder.
git git git, track all my files!
Handy dandy git cheatsheet. Now you can git like you know what you're doing!
See also:
GitHub
Hackers