The flavors are the finalists for their "Do Us A Flavor" contests and their submittees are vying for a chance to win a grand prize of the greater of $1 million or one percent of their flavor's 2013 net sales.
You can vote for your favorite via the Lay's Facebook page, Twitter, or via text message (details on how to vote here). Voting ends May 4, 2013. The winning flavor will stick around until at least the end of the year while the other two flavors may come and go at Frito Lay's discretion (i.e. if they sell really well, they'll probably stick around).
The three finalist flavors were selected from over 3 million fan submissions last year. Once chosen, Frito Lay tested and developed the flavors for production.