via MacNN:
The company says that if users setup mail on their iPhones simply by tapping the "Gmail" icon, the v1.1.3 upgrade will convert access from POP to IMAP. The result is that messages read on an iPhone will also appear as read in the Gmail web interface and any deletions will move messages to the web Trash bin, where they will be permanently deleted after 30 days.You can always manually configure Gmail's IMAP or revert to POP.
The change is just one of many changes that Google made to Gmail this week. Other changes include: automatic refreshing and contact completion on the iPhone. On regular gmail: expanded chat, the ability to integrate non-Google e-mail accounts and larger attachment limits.
Do you know if there is a reason that messages read on gmail.com do not get marked 'read' on the iphone like other IMAP services?
If I read one on the iPhone, it does mark it read on gmail.com, but not vice versa.