One of the highlights is that AOL will switch to using MSN search results. And MSN and AOL will form a joint venture to make a PPC (and I presume eventually a contextual ad network) engine. That PPC bit could be pretty tempting for buyers to have their ads appear on two good sized search portals.
Should be an interesting merger. MSN is alot easier to get new sites into. AOL and MSN's combined over all search percentage will be higher than Yahoo's share.