You would only say "Ciao" (Hi) to a friend. In a report (slightly more formal), you would rather use "Salve" (Hello).
Hi Alfio, can you please add all fixes to a single pull request - or even better register at http://translations.piwik.org since our translations are managed there. Please register and make your changes there. Otherwise it would be overwritten as soon as we pull the translations from there.
@halfdan Thank you. I'll register there.