Y! News and Y! Autos are pretty near (if not) the top of their segments. Mail also has the highest number of registered users. Flickr is a steady revenue stream

Y! News and Y! Autos are pretty near (if not) the top of their segments. Mail also has the highest number of registered users. Flickr is a steady revenue stream, and to a lesser extent so is their webhosting package which is now paid only.