Locking Folders
I think folders should lock by default. It would be nice to be able to set up a regular filter to skip the inbox for certain messages and put them directly into folders (which already exists), but the caveat is that the folders should have an option to require a pin or password to unlock the folder. In essence, this would allow the filter to send the message to the folder, but the folder can only be opened, and its contents viewed if the correct password/pin is input. For added security, it would be cool if the pin/pass was unique to the individual folder. This would be handy when you use an email alias for something a bit more sensitive, and you want to filter messages to a particular folder for an added level of security, almost like a separate inbox with additional security.