XML format for blogs and/or CMS

I'm writing my own blog/CMS engine (using WebApp and Google App Engine), and I'm looking for a light-weight XML format to use for content storage.

Is there some already existing format that could be used for this purposes? Maybe some subset of the DocBook or ePub format? I had a look at those and they seem to be a little of overkill for what I want to do.

Then again WXR (Wordpress eXtended RSS) or the one from Pluxml (pluxm开发者_JAVA技巧l.org) might be suited as well.

Any ideas?

As far as formats for blog content go, it is hard to beat Atom.

That said, XML makes for a really good transport mechanism, but a fairly poor storage mechanism. A real database is usually a better bet.

If this is for compatibility with a specific platform, following their defined schema would be a good idea. Otherwise, just structuring your own XML will work since XSLT gives you the ability to transform the data to other formats as needed.