[shannifin]

Just a letter from the pope, often about how Catholic teaching relates or applies to some modern issue. They present nothing new in terms of Catholic teaching itself, but, through the pope's authority, serve as important guidance for the faithful.

[bigstrat2003]

And honestly, even people outside the Catholic Church sometimes look to the pope for guidance on topics like this - see this very thread. The influence of the pope in the world isn't as strong as it once was, but he still has enough influence that he can do some good with it at times such as these. I think many are hoping for something on the level of Rerum Novarum - I know I am, though of course that's a very tough act to follow.