The link count is the number of hard links to a file or directory.
For directories, this is always (I believe always) 2+number of subdirectories. (The first 2 are the link from the parent to it and it's own '.' reference. Each subdirectory is the '..' in that subdirectory.)
For regular files, this is generally 1, unless there are multiple hard links to that file. (Created with ln FILE SOME_OTHER_NAME).