WordPress 2.6, which was released just a few days ago, contains expanded support for versioning of blog posts, allowing an author to see all of the revisions made to a particular post, as well as to compare various versions and to revert to some previous historical state.
This is a fabulous authoring tool, but it’s all resident in the backend: only the author has access to this versioning information. And for most purposes, that’s probably sufficient. But I could imagine a number of uses — in electronic scholarly publishing, for instance — when one might want the readers of a text to have access to a text’s history. Given that the history is already available, I imagine that it’s just a matter of a plugin that accesses the versioning data, organizing and presenting it on the frontend.
If somebody knows of such a plugin already in existence, I’d really like to hear about it. If not, I hope some enterprising developer starts thinking about one…