Even then, it's not really important to rate posts as long as you can select those worth reading. Many people either want to read only a small number of posts that are interesting, or they want to read all the good posts for some definition of good. Others can easily choose a subset of posts to read from a pool of good ones. Consider that most people don't read an entire newspaper, instead scanning headlines for potentially interesting articles. Subject headings on posts serve (or can potentially serve given the right emphasis) a similar role.
Digests have been around since the Roman times, if not earlier. The Roman encyclopaedia are in fact digests of Greek learning. Academic reviews are very common, taking the best papers from the journals they survey. Heck, even Reader's Digest is a digest of pulp writing. Certainly this is a tried and true technique for filtering content. Moreover, it is sufficiently scruffy that the editors don't need to make the hard decision of ranking the relative worth of posts (is it worth a 2 or a 3?). One merely needs to decide, "Hey, this is interesting."
Then, a potential reader can subscribe to a digest that she likes. The digest picks stuff she wants to read. If it doesn't satisfy her, she can choose another. Thus competition ensures quality. Moreover, alternative editorial biases can be selected by just subscribing to other digests. If the reader is a ContentJunkie?, she can still read the global pool of comments.
Moreover, the load on the host WebLog can be low. If the host WebLog merely holds the global pool of content, the digests can exist on other sites, thus reducing traffic. Hence, it can scale much better than the traditional WebLog.
If the objection is that there is no unified readership to the "community", who cares? In normal society, this doesn't happen and this is good. Diversity should be encouraged. Moreover, there will be mainstream and alternative digests just as there is mainstream and alternative news. However, this way, people can choose not to ignore opinions that would otherwise be filtered out by the global rating system.
And thus continues my evangelizing that voting and rating are violence. Strictly speaking, you could have rating inside a digest. Then it becomes much like Cliff's RatingGroups suggestion on KuroshinRatingSuggestions. -- SunirShah
Great idea. One small comment: this approach might increase the risk of only seeing information you like (or someone similar to you likes), rather than other points of view, or news from fields that you don't normally follow. But actually, this is not a serious problem; one could subscribe to a RatingGroups with diverse raters -- BayleShanks