Although easy to add to documents, Finder comments work strangely, and can prove fragile. They can also be used to conceal malicious code by steganography, but there are better options.
comment
They’re invisible in the Finder, even when it’s showing hidden files. They’re present in many of the folders in your Home folder. And they can do bad things like break your backups.
Finder Comments are accessible, easy to use, and unreliable because they rely primarily on data stored in a hidden file. Regular Comment extended attributes are more reliable.
I regret that I have just had to tighten restrictions on making comments across this blog. Because one […]
When you write a comment to an article here, or edit a Property List, you’re editing XML. Two or three characters won’t work properly.
So convenient to use – edit them in the Comments: section of Finder’s Get Info dialog. But as reliable as loose scraps of paper, and as easily lost.
The Eclectic Light Company 