Could be a problem with my server. Anyway, I'll investigate tonight. It might have been a situation where the mail app actually crashed and I didn't notice, also. But whatever it is, I haven't seen any new duplicates since this morning.
Just got back from McDonalds, where I was able to use the wi-fi (thanks to at&t's new policy of giving free hotspot access to its dsl subscribers). Sweet
And now, a word on the "it is too hard to delete email" comments... Yeah, it's a bit too hard. On chatter I press "d" repeatedly. I wouldn't mind the way iphone does it except that many times I swipe my finger too far and it loads the message instead of giving me the delete button. It would be nice if there was a "tap and hold" to bring up options like "delete," "reply," "reply-all," "forward" etc. without loading the message (and it's easier to tap-and-hold than it is to swipe, imho.)