RSS (Really Simple Syndication) seems to be taking the blog world by storm. Based on the February statistics , I probably have more people who read this blog through my RSS feed than through the Web interface. An RSS newsreader provides a huge amount of convenience for readers, making it fast and easy to track dozens or hundreds of different blogs in minutes per day.

RSS has its limitations, however, especially when it comes to tracking readers and generating ad revenue. It isn't possible to embed Google's AdSense ads into an RSS feed (at least not currently), and an RSS newsreader won't provide any information about whether the reader actually looked at anything in the RSS feed (as opposed to just skimming the headlines).

On the other hand, with current RSS standards, and (I presume) most current blogging software, there's no inherent limitation on how much of the content of a blog can actually be included in the RSS feed. Those who read this blog through my RSS feed know that I include the entire article, as well as any pictures, in the feed (for a good example of this, see my Gunflint articles , which render very nicely in NetNewsWire ).

So the decision of how much of a blog's content to include in the RSS file becomes something of a purity test. If you care about tracking visitors accurately, or generating ad impressions, you need to make the RSS feed somehow incomplete to force people to visit the web site. On the other hand, if you blog purely as a hobby, and don't care so much about advertising or accurate visitor statistics, then you're more likely to include the full content in the RSS feed.

Some examples:

Instapundit : Includes just the first few sentences of the entry, and none of the links. To read the full entry, or follow any links, you gave to go to the web site. Advertising on Instapundit is minimal, but he does use Sitemeter , so he probably does this to track visitors.

Volokh Conspiracy : Includes full entry and all links. The RSS feed renders badly on NetNewsWire, so I presume it was tested with some other reader.

Wonkette : First few sentences, no links. The site has both Sitemeter and extensive advertising, plus Wonkette is a professional writer. She's presumably trying to make a living at this.

Calpundit : First few sentences, no links. Also now blogs for a living.

BBC : Headline and first sentence only. Actually very frustrating, since it can be hard to tell if you're interested in the article from the little that's included in the RSS feed.

Space.com : Headline only. Almost useless. This is an advertiser-supported site, but they don't get much traffic from me because I can't tell if I'm interested from a five-word headline.

Ventureblog : Full content and links.

BoingBoing : Full content and all links and images. Very useful.