I've thought about implementing something like this; but, I keep coming up against two different arguments:

1. I think there's value to having people come to your site. Not just for traffic, but to keep them involved and aware of changes to the site.

2. Content being posted in the email can be far more complex than the content being posted in a simple Textarea. There's a nice dependency on the clean input of a textarea and a form submission. With rich email clients, you just need to take more care.

... of course, maybe that's just me being intimidated about thinking about the whole workflow in a different way than I'm used to.