Ever since Lion (OS X 10.7), Apple has hidden your personal Library folder (~/Library) by default. In Lion and Mountain Lion (OS X 10.8), you could make the folder visible, but it required some work. In Mavericks (OS X 10.9) and Yosemite (OS X 10.10), it's a simple, easily accessible setting.
Apple releases a critical security update that affects OS X Mountain Lion, Mavericks, and Yosemite users.
Apple has issued a security update for OS X Mavericks and Mountain Lion meant to protect Macs against possible POODLE attacks.