Hi.
There are a couple of enhancements on beta in the mailbox screen at the moment.
One is that we display some additional information in the "F" (which stands for flags) column. We show if the message is a high or low priority message (currently as defined by X-Priority:, but we can easily check other headers as well), and also if the message has been flagged.
You can flag a message using "Mark flagged" from the action drop down. This just sets the IMAP \Flagged flag, so you can also see which messages are flagged, and set the flag on messages using an IMAP client.
Also, there are some quick flag searches available at the top of the message list. You can view only the messages you have read, or only the unread messages, or only the flagged messages (or all messages, of course).
If any of this sounds like it would be useful to you, log in to
http://www.fastmail.fm/beta/ and give it a try.
Richard.