Brad Kellett read my earlier post in which I mentioned that Word 2007’s new blogging feature seems to send posts into the WordPress ether. Brad says there’s another explanation:
I don’t believe that this is a problem with posts disappearing, just that they are getting a post date of far into the past – in my case, it was December 1969. For everyone having trouble posting from Word 2007 to a WordPress blog, fire up your admin console and head to Manage > Posts and change the browse month dropdown to whatever is the abstract date.
Absolutely right. In my case, on a notebook running Vista Beta 2, the posts were dated November 1999.
Not sure I want to go back to either of those dates, to be honest. Thanks for the pointer, Brad!
Ed Bott 
It’s noted in the help file…
Well, that’s technically correct. The help page notes “Post date is incorrect” in reference to WordPress. But I didn’t expect it to be off by 37 years!