This means that now when you type in a query in Yahoo! UK it will now give suggestions.
"Yahoo has also been beta testing Search Assist, which I happen to now see as of this morning. Search Suggestions On Steroids: Yahoo Search Assist from Danny Sullivan a while back, showed off many of the features of this new beta interface. I am personally able to see it in New York, but I asked other people in the US if they can see it and they were not able to."