I don't get enough emails. I'd like to get email notifications when one of my posts is "liked" by other members.
There is precedent for this. The old Engadget.com comment system sent me emails when one of my posts was "liked" by other members.
Subject should be: "[Member Name] liked your comment in "[Topic Name]"
A link to the thread and an "unfollow" link should be provided in the email body.
There are enough likes being handed around such that members may feel a greater sense of reward or satisfaction in receiving the emails. Further, the emails could increase user engagement in the same way as when someone quotes someone else's post and that user receives an email indicating their post was quoted.