Mark Pilgrim has removed the link element from his RSS feeds, favoring guid to represent permalinks, the method advocated by Dave Winer. Though this method is technically appropriate it introduces a severe problem.
Many popular aggregators, including NetNewsWire (we've been told) and Syndirella, which are, incidentally, each recommended by Mark, will not display guid content. Mark makes this problem worse by including only excerpts in his feeds. In other words, Mark is sending feeds to users who, if they are using the aggregators he suggests, will receive only summaries of articles they are unable to access. For example, we see only the following in Syndirella for Mark's latest entry:
We've all been guilty of trying to remake RSS in our own image. (642 words).
No link. No real content. We've heard this casually called "less than ideal." Less than ideal? It's unacceptable. We're as interested in conforming to the spirit of standards (and formats) as anyone, but we can't understand why anyone would use a format designed to provide content in such a way that hides content from users.