Selective e-mail notifications
Short, concise description of the idea
Ability to have email notifications off by default and have them turned on selectively per post.
Full description of the idea
This would pretty much be the opposite of the "don't email comments" option that is available in some clients. That feature allows you to selectively disable comment emailing when you have "Get message board replies" enabled. This would allow you to have the feature off by default, but give you the ability to enable it for an important post, one that you might not remember to go back and check for comments, etc.
An ordered list of benefits
An ordered list of problems/issues involved
An organized list, or a few short paragraphs detailing suggestions for implementation