They could also try sell to private equity, or someone like John Malone & Liberty Media. I think even a separate capital stock of the core assets would force more value recognition than what shareholders are seeing now, even as a low priced issue. I'm not sure that Google would want anything here that they couldn't build themselves or don't already have the lead on, but if there's any interest, Yahoo should solicit those offers.
Yahoo Search and Yahoo Mail are two assets that GOOG and MSFT would be suitors for. MSFT/MSN looks like a good suitor too, but you never know. From Mayer's side, since she is Google alum, there can be something out there.