The never ending parade of new features in Gmail keeps rolling, and there are two new ones worthy of note.

First up is “undo“.  Ever sent an email and immediately realized you forgot to copy someone on it, or you forgot an attachment?  Well, with this new Labs feature, you have about a five second window after you click “Send” to click on “Undo” and correct the problems with the email before it goes out.  While it’s a great concept, it failed on my first test of it. Yes, I got to edit the email, but the test recipient also got the wrong version of the email.  If they work this out it will be fantastic, but not quite sure about it yet.

The second new feature is previews of YouTube videos in your email.  Although we aren’t quite sure why they are calling them “previews” as our test allowed us to watch the entire video from inside the email we sent.  This is highly useful for when you forward emails to friends, they will no longer need to go over to YouTube to watch as it will be automatically included in the email while they are viewing it.  As you can see from the example below, it can also handle multiple videos, so next time you are sending around a viral video, your friends will be able to save themselves a step.

As with all Labs features, you will need to click on “Settings” in the top portion of your Gmail screen, click on the “Labs” tab, and then locate them to enable them in the ever growing list of new features that Google is adding to the service.