I'm at the SES right now, and the Yahoo product director just announced Yahoo Search Builder Looks pretty interesting - sounds similar to eurekster from his initial description, but I don't know for sure. Scratch the eurekster comment - it's really just a nifty customizable site search wizard. Still interesting, though.
similar, yes. I suppose it would be useful if either a) it fits into your site design a little better; b) you like having a "search news" option; or c) your yahoo indexed pages is larger than your google indexed page count.