I would like to install some Firefox add-ons, also called 'extensions' or 'plugins', like for example Adblock Plus, Ubufox or Greasemonkey.
Should I install them from the Mozilla website, using the Firefox browser, or should I search Firefox in the Software Center and then select the interesting applications ?
I suppose the issue is about how the extensions are kept up-to-date. If your answer is 'via the Software Center', how can I migrate well from my former add-ons without losing all my preferences?