How does this relate to existing OG subscriptions?

Could you clarify for me how this works with or supersedes the existing OG email subscriptions? Currently, with your module installed, the user sees on their account edit page three or four mail-related fieldsets and this is very confusing. There are: Private message settings, Organic Groups Settings, Notifications settings, and Messaging settings. Oh, and throw in the Contact settings fieldset which also sounds similar. It seems to me that these would be better displayed under one "Messaging" fieldset or something.

But I'm getting off track -- what I really want to know is whether users need to select either "Selectively send email notification based on the checkbox for each of my group's My Subscription page" or "Always send email notifications" to get email digests from your module, or if they can subscribe to posts even if they selected "Never send email notifications. Useful when tracking activity via RSS feed instead." Or are these options independent? If so, will they conflict? If these controls are not needed, could you provide an option to hide them?

Also, I see references to mail digests, but no explicit settings. Does setting the interval to anything other than "As soon as possible" create a digest of posts? Perhaps the help text should be updated to reflect that if so.