One of my big pet peeves with syndication is when platforms publish multiple formats. Or, more precisely, when the user is presented with 5 similar-looking icons with all of those options. Why make the user think? The user wants your content, but you've put an additional barrier in that ultimately has little or no effect on their consumption.
Many argue that ATOM is a superior format, and from a technical perspective that is probably the case. I just can't bring myself to care all that much. ATOM makes certain things easier (or even possible) for the developer. If I were developing a publishing platform or an aggregator, I might feel more strongly about it.
But as a publisher and consumer of content, I don't care how syndication happens. I don't care if you're sending me RSS 0.92, RSS 2.0, ATOM 0.3, or ATOM 1.0. I don't care how you encode and escape and cache the content. Those are technical details unimportant to the consumption and creation of the content. Much of the appeal and success of blogging is that these platforms and standards have eliminated technical barriers to publishing and consuming content. Among the groups who have a vested interest in syndication, the producers and consumers have the least incentive to care as long as it all works.
We do have a universal standard for syndication: XML.
The reason syndication formats don't matter is that they're all XML. First of all, XML can easily be transformed from one format to another. It is relatively trivial for me to convert from RSS to ATOM and back. And you can always use FeedBurner, which (among other things) "translates your feed on-the-fly into a format (RSS or Atom) compatible with your visitors' feed reader application." If your aggregator supports ATOM, that's what you're getting. If not, the feed degrades gracefully until we find a format that works for you. Secondly, XML is - as the name suggests - extensible. The RSS specification may be frozen, but I can easily add additional information to my RSS feed without breaking existing aggregators.
Furthermore, as aggregators become increasingly commodified, they they must "be liberal in what they accept from others" to have any chance to compete. They must necessarily support RSS and ATOM, and they will continue to have to do so as long as there are RSS feeds that their users want to consume. this group probably has the most incentive to standardize on the easiest format - but unfortunately they're not in the position to make that decision unless it's unilateral. And you know what? If I were writing an aggregator, I would just transform all of the other feed types to my feed type of choice to support the greatest amount of content.
That is the beauty of XML, and that is why syndication formats don't matter.
Conceptually, syndication is very important, but like AJAX, the spirit behind it is unfortunately tied (by name) to a specific implementation. RSS doesn't matter; ATOM doesn't matter. What matters is the fact that content can be syndicated, and I will consider this movement successful when anyone can subscribe to content and not know - or care - how it actually happens. Right now, we're not far from that ideal.