Let's talk about this not as users of WW. We're all coming here and liking it, so this is isn't going to be a biggie for most. I'd be interested this topic, overall, in context to WW.
So, to get new users more involved and bring back those who drift out, an email newsletter for this type of site could have value.
Yes, opt-out, certainly. And, yes, it should carry an ad. And, there should be some foo-ish to it, always. (The Washington Post recently started a daily newsletter like this called "The Most." It is links to the most viewed stories in the last 24 hours. For WW, weekly would be fine.
Right. You only get a percentage of your audience and I do not recommend a newsletter-only effort.
I tell people that email newsletters are not THE answer. There is no single answer to driving traffic to your website. It's about doing a lot of things right. And, for many, email newsletters can be useful.
Have you used email newsletters to drive traffic to your website? Do you think Brett should?