I've always thought email marketing (and the company newsletter in particular) was undervalued. So long as it is opt-in and so on, email is a brilliant way to get your brand in front of your constituency with great repetition at extremely low cost.
The issue, as this article points out is frequently that there are legacy problems with the list - in that it has old addresses and segments like clients and suppliers mixed together. As a result, it's hard to distribute with confidence and without spamming. However, to have an email database that is unused is essentially the same as not having a list at all so it seems to me that many companies would do well to ditch the legacy problem and simply start afresh.