Every since Yahoo! launched Site Explorer they had dreamed of redirecting any of you who did a link, linkdomain, site command on search.yahoo.com to siteexplorer.search.yahoo.com. Today, reports via Search Engine Watch Forums, Yahoo has done just that.
The thread creator states that when he conducted the search, it brought back a message
Your "linkdomain:" query has been redirected to Site Explorer. You can continue to use normal web search for other queries.
I personally try this out at search.yahoo.com and it keeps me there. So they may be testing this out on some users. But I know for a fact, that Yahoo! had plans for this move.
Forum discussion at Search Engine Watch Forums.
Update: Yahoo! has confirmed this with me, this is a test some users at Yahoo! will notice when conducting these style of queries.