With the availability of OS X Yosemite in the Mac App Store, Apple isn't stopping an end to the public beta program it had created to allow customers to test new features before a larger launch. Instead, Apple will continue the beta program for customers who had participated in the OS X Beta Program. However, if you're done being a tester, Apple is also giving you an option to opt out of future beta updates as well.
In an email sent out to the public beta community, Apple wrote:
As a member of the OS X Beta Program, you will continue to be offered beta versions of OS X software updates on any Mac that you installed the beta on.