Forum: Typo Typo email notification for comments

Hello guys,
I'm wondering if it's possible to add a checkbox in order to let people 
that make a comment in a my blogpost to receive notification whenever 
another comment is posted but someone else.

I can't understand how typo works so I can't provide you a patch (all my 
attempts failed flawlessly).

Thank you!
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Fabiano Francesconi [GPG key: 0x81E53461]