Apple has seeded the second beta of OS X 10.10.1 Yosemite this evening. The update, labeled build 14B23, is available through the Update tab in the Mac App Store and the Mac Dev Center for all registered developers.
Today’s release comes just one week after the first beta, and nearly a month after 10.10 went public. It's not clear what changes it includes yet, but Apple has asked devs to focus on Wi-Fi, Mail and Notification center.