When you signup we spend some time trying to understand you by exploring your Twitter profile (followers, links, retweets etc.). Once done, we either recommend you an article from a curate pool of articles which we've come across before, or by browsing sources we think will have interesting content which you might not be looking at already.

We then send you an email with a link to the content and an explanation behind our reason. If the user replies or reads the link, we keep going. If they don't we stop! Ultimately to do this well, we want to have a conversation with the subscriber (almost like bibliotherapy).

For example, were someones Twitter data points indicative of an interest in Programming Languages and Education, we might send them http://worrydream.com/#!/LearnableProgramming, with a brief explanation on why. If they reply saying they don't like long form, old content, then we'd make sure to adjust the next article accordingly. Hope that helps!

I agree, I have no intention of giving out my e-mail without an example.