If LimeWire is sharing more files than you have in your shared directory, I would suggest that you have also shared some other directories. LimeWire is not limited to the directory that happens to be named 'shared.' It can, if you instruct it to, share other folders as well.

Generally the folder where you download to is shared as well, and if when you installed LimeWire you let it scan your hard drive for files to share, other directories with media will be shared.

It's pretty easy to find out which ones are shared.. just have a look at the library tab, the upper left pane. If more than one directory is listed there, you have your answer