Robin Good: One of the best ways to provide valuable content to your fans and potential customers is to serve them a periodical digest of some really precious gems. Few and very good.
This approach is the opposite of what most companies do when it comes to sending out email updates. They direct all of their effort at promoting their own news and stories, but often these are not worth much in the eye of the reader.
Selecting instead some quality resources, few and very good, and serving them periodically to your subscribers can be an excellent strategy to gain reputation, trust and authority.
Here a few good examples to inspire yourself:
Via Robin Good