Google has introduced Priority Inbox, a new Gmail tool that aims to prioritize e-mails based on their importance. Gmail has always been pretty good at filtering junk mail into the “spam” folder.

But today, in addition to spam, people get a lot of mail that isn’t outright junk but isn’t very important—bologna, or “bacn.” So we’ve evolved Gmail’s filter to address this problem and extended it to not only classify outright spam, but also to help users separate this “bologna” from the important stuff. In a way, Priority Inbox is like your personal assistant, helping you focus on the messages that matter without requiring you to set up complex rules.

Priority Inbox splits your inbox into three sections: “Important and unread,” “Starred” and “Everything else”.

As messages come in, Gmail automatically flags some of them as important. Gmail uses a variety of signals to predict which messages are important, including the people you email most (if you email Bob a lot, a message from Bob is probably important) and which messages you open and reply to (these are likely more important than the ones you skip over). And as you use Gmail, it will get better at categorizing messages for you.

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Another day, another new feature in Gmail Labs. This one could be more useful than most, as it’s something you probably have a reason to use with some frequency. It’s called ‘Undo Send,’ and as the name suggests, it lets you take back a sent email, as long as you act quickly enough.

After enabling the feature, Undo Send works much like Gmail’s other ‘undo’ features. When you send an email, you get a message confirming it has been sent, along with a link to ‘Undo.’ This message lasts for 5 seconds, at which point you lose the opportunity to take it back. While that might not be much time, it’s probably enough to pull back emails where you forget an attachment, forget to cc someone, or catch an obvious typo.

Well, hey .. it’s handy.