The smoke from the papal chimney is black, meaning that a vote was taken amongst the 115 cardinals but no pope has been elected. It was always unlikely that a pope would be elected on the first day, as this is close race without a really clear favorite.
In 2005, the conclave that elected the previous pope, Pope Benedict XVI, lasted just one day, one of the fastest in history, in that case Pope Benedict was widely regarded as the favorite due to his extremely close relationship with Pope John Paul II. There was even a chance that would we see no smoke emanating from the chimney, a signal that no vote had taken place. It will remain unknown who voted for whom as the election ballots are burned, creating the smoke. This conclave is widely expected to go on for more than four days.
In 2007, Pope Benedict altered the rules for electing the new pope, he allowed a new candidate to require just 2/3 of the vote.