The recent animosities by no means endanger a Yahoo!/eBay merger:
Google was ready to invade eBay's Live event, which made eBay pull away from AdWords. Instead, eBay could be a bigger Yahoo! partner. Google attacked Microsoft over Vista's desktop search. The case was settled.
Nor do the recent advances, quite to the contrary:
Yahoo!'s problems keep any merger speculation alive, particularly with Microsoft. Now the Times of London reports that News Corp (NASDAQ:NWS) floated the idea of swapping MySpace for a 30% Yahoo! stake. I believe the implied MySpace valuation must be too high for Yahoo!, which proved quite frugal when approaching Facebook. Also, I believe that Yahoo! needs to be a 'content neutral' aggregator, not a News Corp vehicle. However, the eBay/MySpace talks are still ongoing. Yahoo! has not responded to Ron Burkle's attempt to involve Yahoo! in a counter offer for Dow Jones, News Corp's much desired prey.
In other words, I think Yahoo! is carefully aiming for eBay. At the same time, News Corp must be kept at an arm's length.