Two types of aggregators
Ziv Caspi: Atom 0.2 is out. Although not an official spec, it looks like it's now solid enough to comment for people who are, shall we say, wiki-shy. So here's mine.
Lots of good feedback here. Ziv talks about two types of weblogs - "take that" and "phone home". I think the distinction is more subtle than that, and deserves further exploration.
But first, I'd like to point out that there are at least two types of aggregators out there: most fall into essentially two camps: "single page", and "three pane". This difference will be explored in a bit.
Back to the "two types of weblogs", let me explore this by looking at two specific blog tools, namely, Radio UserLand and Movable Type. Radio UserLand was my first blog tool. While you can do many things with it, let me focus on two: posting to your weblog, and creating a story. Posts tend to be short. Stories tend to be longer. Posts are included in your RSS feed. Stories are not. To get a story to appear in your RSS feed, you merely link to it in a Post.
Movable Type is different. Not necessarily better or worse, merely different. There is one type of entry. It can be any length. Once completed, it the results can be made to show up in three places: your front page, a page dedicated to this entry, and one or more feeds. By default, all three show the exact same thing. This may be suboptimal for essay length content, so this can easily be overridden. In fact, one can separately control the content that shows up in each of the three places. What this means is that you can create a story with a separate lead in blog entry entry. You just do it using a different series of steps than you do with Radio UserLand.
Now lets look at this from a user of an aggregator perspective. If you are an online user of a single page aggregator, then what generally best suits you is a a short lead in with a link to the rest of the story should you be intrigued enough to follow it. If you are an offline user of a three paned aggregator, seeing only the short lead in is - to put it quite bluntly - a tantalizing and quite frustrating tease.
If you are a content producer (i.e, you have a blog), it is not possible to serve both audiences with a single RSS 0.91 feed. RSS 0.91 had one "slot" for a description. This tended to favor the online users of single page aggregators. With RSS 1.0 and 2.0, it became possible to address this need via namespaces. In fact, the most popular module that is used in both versions to address this need is mod_content. The conventional usage pattern is to put the summary in the description and the full story in the content:encoded element.
This allows a single feed to address both audiences.
The Atom 0.2 Snapshot provides both a summary and a content element in the core.
This weblog post is longer than most of the ones you typically see on my weblog. In my RSS 0.91 feed, you only get the excerpt. In both my RSS 1.0 and RSS 2.0 feeds, you get both the excerpt and full content. On my front page, you will initially see the entire content. Once it moves down the page, it will be replaced by the excerpt. Ultimately, it will drop off the front page completely.
In either case, the link will take you back to the full content on a separate page. Furthermore, what you will find there is often far more valuable than the original post: comments. On my weblog, that's often where the "good stuff" happens.