Stamps with the words "Sede Vacante” have already been made. Even a series about the Pope's resignation has been published, which will undoubtedly become a collector's edition.
In the coming days, St. Peter's Square won't be as busy, since there will be no Sunday Angelus or even a weekly general audience. The windows of the papal apartment are completely closed and now at night, the lights at the Pope's office are always off.
That light, emerging from the Pope's office was a symbol that pilgrims looked forward to seeing night after night. It meant that the Pope was at work, governing the Church.
It's a different and unique situation, since there is no need to mourn the death of a pontiff. There's no need to organize a funeral or any religious celebrations which up until now, have preceded all conclaves.
During the Sede Vacante, it's not uncommon to see cardinals walking through nearby streets. Even the city of Rome put up posters to thank Benedict XVI for his pontificate.
The Church lost a Pope and now it looks for his successor. Rome feels this absence, but its comforted by Benedict XVI's words. Before leaving this pontificate behind, he said he would still be there, through prayer.