Why is my session being reset when I POST/DELETE in Rails 3?!

In Rails 3, the InvalidAuthenticityToken error is no longer used. Instead the submit will fail silently and reset your session.

This totally baffled me when I set up a javascript to POST my delete links and I suddenly started getting logged out. You have to remember to include the authenticity token to protect against this symptom.

http://stackoverflow.com/questions/6090063/rails-3-protect-from-forgery-not-working-correctly