From the Jet.com page:
We are getting amped to launch Jet.com early next year. While we aren't quite ready for our public debut just yet, we wanted to create a fun pre-launch program to fuel the growing excitement around the shopping experience we are building here.
Today, we introduce Jet Insider. We invite you to sign up at Jet.com to become a Jet Insider and reserve your spot in our pre-launch line. Just submit your email address and you will receive a free 6-month membership to our shopping club along with the chance to compete with other Jet Insiders to earn up to 100,000 shares of Jet Insider stock options. (The same amount we’ve given out to some of our earliest, high-level employees.). Check it out.