MSWord and other Office tools use the "old" Mac line ending (CR aka \r aka 0x0d) when producing plain text files. Other text-producing tools (including, but not limited to, TextEdit, Emacs, Nano) use the standard Unix ending (LF aka NL aka \n aka 0x0a):

-> od -c word.txt 
0000000    1  \r   2  \r   3  \r   4  \r   5  \r
0000012
-> od -c textedit.txt
0000000    1  \n   2  \n   3  \n   4  \n   5  \n
0000012
-> od -c emacs.txt
0000000    1  \n   2  \n   3  \n   4  \n   5  \n
0000012
-> od -c nano.txt 
0000000    1  \n   2  \n   3  \n   4  \n   5  \n
0000012
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All of the above files (created under Mac OS X) are one digit per line (as viewed in the application in question).

Use ikegami's code from above reply to convert existing old-style files and use one of the non-Office text editors for editing plain text (choose the one you are most comfortable with; other options available on Mac OS X include vi or vim).