Feeds are fairly flexible and dynamic. You can add all sorts of content to them and publish a podcast through the same feed you may be using for normal text content. It is possible to create multiple feeds from one main feed using categories so you could publish a single site feed and then publish individual category feeds to enable users who want them to only subscribe to the specific content they want. For those people who prefer to receive emails, you could easily provide your feed by email using Feedburner or Feedblitz, for example. If you use a blog or other content management system (like Drupal or Joomla) you have a few options for the distribution of your content. You are already publishing your content on the site itself. The blogging software or CMS is publishing a feed based on your content (probablly a variety of feed options) and you can easily add feed-to-email distribution as well.
An interesting point was made on the Read/Write Web post about summary/truncated feeds and full feeds. A report by Pheedo published last year seems to indicate that in some instances summary feeds are more effective than full feeds and in others it works the other way around. One argument in favour of a summary feed is that an abridged feed forces readers to visit the source site and this protects the readership of the site itself (this is a bit like a trailer for a movie). An argument in favour of full feeds is that people should be able to access the content in their chosen medium and if users want to read your content in a feed then they should be entitled to do that. I am more in the full feed camp myself. If anything, reading a summary feed tends to put me off the site itself and I often visit the source post even with a full feed because I may want to blog about that post and would need link details for the post.
All in all, there is considerable merit in using feeds in your marketing initiatives. I do see feeds as being part of the overall picture and an increasingly important part of that picture.