"Quote selected text" changes Gmail's replying behavior and it lets you include a selection from the original message. This is especially helpful when you reply to long messages from people who don't use Gmail. Your reply will only include the necessary context, not the entire message.
This experimental feature works only when you use the keyboard shortcut for replying (r), not when you click on "Reply".
"Reply to all" changes the default replying option when you receive messages addressed to more than one person. Instead of replying only to the sender, the default option changes to "reply to all". Just make sure that your reply is really useful for everyone.
"Vacation time" is an enhancement of the vacation responder that lets you enter when you intend to go on vacation. This way, you won't have to remember to turn on the vacation responder. "While planning my own vacation, I didn't want to worry about composing, starting and stopping my vacation auto-response while I was on vacation. Call me a purist, but that defeats the whole point of being on vacation," explains Darick Tong, the author.
What other features would you like to see in Gmail Labs?
{ via Gmail Blog }