They also own flickr, which I'm sure you knew.
I am quite certain that people would care if these things, along with their @yahoo.com email addresses disappeared tomorrow. I'm sure you knew this too, because email is central to our online lives at this point.
So okay, you actually do know what yahoo does. What you don't know is their purpose. Google's purpose is to index all the worlds information (and then slap ads on it, but first one, then the other.) Apple's purpose is to make really great products, and then market them so well that people think they're even greater.
So, given what we know yahoo has, what's a consistent product story they could tell that would answer the question that comes up again and again?