“The practice is gaining ground in places like Silicon Valley, where start-ups spring up like weeds and venture capitalists who have never seen a timecard make little if any distinction between ‘work’ and ‘nonwork’ time for themselves or their employees. For employers, the benefits of unlimited vacations include not having to use staff time to track and record vacation hours. There’s no need to pay employees for their ‘accrued’ vacation time if they leave; they don’t accrue any. Among the companies that have already put an unlimited vacation policy in place are Netflix; Best Buy; Zynga, the online game maker; and Rodale, the magazine publisher.”
http://www.csmonitor.com/Commentary/the-monitors-view/2013/0822/Would-you-like-unlimited-days-off