Do you mean to vote for the Italian elections? Of course, if you are a citizen over 18 y.o. but are residing abroad, you have the right to vote (even if you have never set a foot in Italy nor paid Italian taxes!).
You have to made aware the Consulate that you are living in their consular district, and provide a residential address where your voting card will be shipped (I think directly from Italy). Then you mail your vote (I believe directly to Italy). The candidates are different from those available to Italians residing in Italy - they represent Italians abroad in the Italian Parliament. Their number is limited. However, usually the voting card get lost in the mail or arrive too late to vote or after voting has closed.
Though there is for sure some rigging, the influences of those votes is so small, nobody cares.
I think you saw some posters telling people to register at the consulate (as Italian citizens residing abroad) in order to be able to vote.