I assume an HTTP Expires header for Atom content will work and play well with caches such as the Google Accelerator (http://webaccelerator.google.com/). I'd also guess that a syntax-level tag won't. Is this important?
The HTML solution for people who could not implement Expires: seems to be META tags with in theory equivalent information. Though in practice the whole thing is a mess, this seems like a conceptually simple workaround. Is there something obviously wrong with it?
-John
