The Distributed Link Tracking Client is used to maintain links to files on NTFS volumes on a computer or between computers in a domain. These links can be both shell shortcuts (like the ones in your Start Menu) as well as OLE application links (such as an Excel spreadsheet stored within a Word document). This keeps a shortcut linked to a file even if the file is moved, and is most useful in an enterprise environment where files are stored on network shares. On a home computer or home network you probably won’t miss this one to much, so it’s safe to disable, but if you move files around, you may have to manually fix shortcuts.