I configured my Email app to point to an existing Yahoo Mail account.
When I go into the Sent folder, I see that the Android-composed messages display the recipient (To:), but the older messages display the sender (From:)
I checked the headers on several messages. It seems that Email app is selecting first occurrence of "From:" or "To:".
So my older messages say...
...and the "From:" is displayed in the message list
The new messages I composed in Froyo have:
...and the "To:" is displayed in the message list.
Is this the expected behavior? I know that some things are different in mobile world, but classically, the "Sent" folder has been special cased to show who the message is being sent to, because that is the most useful information to display in this context.