Originally Posted by
brewbuck
A directory always has at least two links: it links to itself (the "." entry in every directory is a reference to itself). There is also a link due to the parent directory which contains the directory. A file has at least one link, for the directory entry which references it.
A "link" in this case is not a symbolic link. A link is a mapping from a directory entry to an inode. The number of links to an inode is counted within the inode itself -- this is the number which "ls" is reporting. A link count is always at least 1. A link count of 0 would indicate filesystem corruption.
Basically it's the number of "pointers" which are "pointing at" the inode.