Chen , Stephanie. Where 'Undo Send' and other Gmail ideas are born. CNN. March 25, 2009 http://www.cnn.com/2009/TECH/03/25/gmail.labs.email/index.html?eref=rss_tech

Gmail the email program developed by Google has a special function called Gmail labs. In Gmail labs special features such a undo send feature and a feature that prevents drunken emails from being sent are available to willing users. Google uses Gmail labs like a test market to see what features Gmail users would be most likely to use with the intent that the features that received a good response would become a part of Gmail. To encourage innovations Gmail lab engineers are allowed to devote twenty percent of their work week to their own projects. With the undo email feature once a email is sent a window will pop up and remain for 5 seconds so a users can check to make sure that the rely to all button was not pressed. To prevent drunken emails, one feature requires users to do a series of math problems before being allowed to send emails between certain hours specified by the user. Another feature prevents a user from checking their email too often. Google maps came out of Google labs so just maybe the next standard part of the program will be out of Google labs.
I find it interesting that Google has programs such as Google labs but one should expect such innovations from a company that was born on new ideas. It is a good and cost effective way to promote new ways of thinking and test would the Google using public wants. I do not use Gmail but I may start just to see the 36 features available from Gmail labs.