Jane, it is possible to leave iTunes open and sharing a download folder. This
makes it possible to inadvertently share everything that was downloaded by
accident as well as by choice.

I always advise people not to share the downloads folder at all because not
only are you automatically sharing stuff before you get a chance to check it
for viruses, worms and contraband like illegal porn, but you may also be
infringing on copyrights if somebody comes along later and uploads some of
the perfectly legal files you downloaded.

Don't worry about the illegal web sites that distribute underage porn. They
are always found, no matter where in the world they try to hide, and the
police in all countries are always willing to work together to arrest whole gangs
of these criminals and their customers whenever and wherever they are found.

LimeWire, on the other hand, is not a web site or porn distributor. It is just a
piece of software people use to share and explore for whatever they want,
and it has no control over what people do. One may as well blame Internet
Explorer too.