Any of these services could be affected by the Yahoo! Breach. It's hard to find a master list.
- "The 20 Startups Marissa Mayer Has Acquired at Yahoo" by Mashable
- "List of Yahoo!-owned sites and services" from Wikipedia
- "List of mergers and acquisitions by Yahoo!" from Wikipedia
And that doesn't cover the 3rd party OEM deals they've struck. Here in Canada, Rogers used/uses Yahoo! for a lot of the free services provided to internet subscribers.