Larry Tesler is redesigning the Yahoo homepage. His design philosophy:
…Everything has to be very fast, which can be an issue on the Internet, and be very simple. Sometimes things appear to be simple, but aren’t.
The other thing I’ve been pushing hard since I got here is that using Yahoo should be a delightful experience. I’m [...]

According to Majestic Research, Google Search accounted for only 21 percent of the time that U.S. visitors spent on the Google site during June. In contrast, 45 percent of the time was spent on Gmail.
Yahoo visitors spend only 2 percent of their time searching, while 42 percent of their time they used Yahoo Mail and [...]

Great article at SearchEngineWatch "Revisiting Hijacking & Redirects: Moving To A Solution" explains how Yahoo and Google handle redirects.
Yahoo:

301 Permanent Redirect
source-domain –> target-domain = target-domain URL kept and used for listings

302 Temporary Redirect
source-domain –> target-domain = target-domain URL kept and used for listings
301 permanent redirect
root-page –> [...]