Gmail today added two extremely useful and functional features to Labs. You know Labs, right?
The first one is Nested Labels. Yup, that’s right. Now you can create labels within labels creating a tree like structure as shown in the image below.
If you think this is useful to you, go to the Gmail Labs tab under Settings, look for "Nested Labels," enable it and click "Save." You'll then need to name your label with slashes (/) to make it the child of another. For example, let's say you wanted to create a simple hierarchy with a "Home" label, and inside it a "Family" and a "Vacation" label. Just create three labels with the following names:
Google says that this particular lab feature doesn't play nicely with the "Hide Read Labels" lab. You might not get exactly what you expect if you have both labs enabled; for example, the collapse/expand icons won't always appear when they should.
The second lab feature is called "Message Sneak Peek”. This one allows you to preview messages without opening them. Simply right click a message to open a preview pane with the message on it. Messages you peek into will stay unread until you actually open them.
Another lab feature I highly recommend is Inbox preview that lets you preview your inbox while you wait for the page to load.
[via Gmail Blog]