Return Path is reporting that as of January 2009 Yahoo! will be using the SenderScore Whitelist.
To Quote Alex Rubin, VP Business Development with Return Path:
During the first week of January, Yahoo! will begin using Sender Score Certified status in their filtering decisions. This means that Sender Score Certified members will receive preferential treatment in reaching the inbox at Yahoo! Mail.
Also SenderScore users will begin to receive delivery feedback in their daily reports starting in December.
Sources at Return Path say this will not be an option for Safelist (formerly Habeas) clients, and only the Sender Score Certified clients will be active in this service.