It's Going to Be a Two-Engine, 80/20 World The l france email list atest figures suggest that Google continues to slowly gain market share in the US, while Bing & Yahoo! compete for share that will eventually belong to them both (once the regulatory hurdles clear, which I think they will). I believe that a year from now, most webmasters will be looking at a scenario where Comscore/Hitwise reports Binghoo! has ~25-28% market share, but those engines combine to send a little under 20% of all search traffic (remember that they count searches on all Microsoft and Yahoo! properties - even internal searches - while Google tends to send the vast majority of their search traffic externally to other sites).
I hear out of Yahoo! and Bing is that Site Explorer is off to the great beyond. The expense of maintaining a web index isn't something Yahoo!'s willing to invest in once they don't have to, and Bing's given no indication that they're going to re-open the portal to link information. The best we can hope for is an acceleration in the functionality offered by Bing Webmaster Tools, but even that's unlikely to offer competitive link intelligence.