Only what's in your shared folders. Go to your LW Library window & what's in those folders you see will be shared. It means that if people are searching for a particular file, one of your files may show in their search results. To know for sure, look to the columns to the right. Hits shows how many times each file has been found in someone's search. Uploads shows how many times they have uploaded or attempted to upload your files. Concurrent uploads can be seen in the Monitor window at the bottom.