Also consider paths like C:/path/./to/./file -- that's equal to C:/path/to/file.
The dot is pretty meaningless.
It's mostly useful when you want to be explicit in the case where multiple directories are going to be searched for your input.
e.g. let's say that when you type 'notepad.exe' the windows command line, it first checks inside the system32 directory (i'm not sure if this is true) before checking the current directory.
If you wanted to be explicit that you meant the notepad.exe relative to the current working directory of your shell, you could type "./notepad.exe" instead, because the shell will resolve your dot-containing-input into a full path before it searches for that file.