One of the most annoying features in Ubuntu from 12.10 onwards are the pesky notifications popping up asking if you want webapps support everytime you visit a supported webpage?
Whilst you can disable this in Firefox’s browser options: Firefox > Preferences > General: Uncheck “Prompt integration options for any website”.
However I prefer to remove the browser extensions entirely.
sudo apt-get remove xul-ext-unity unity-chromium-extension
NOTE: Take care – unfortunatly you can not remove the following as their removal will cause Unity to fail !