Back in 2011, Bing Webmaster Tools began adding Yahoo data to their reporting tools.
At the top right of the charts, it reads "Combined traffic data from" with a Yahoo and Bing logo. But some are asking of Yahoo data stopped working.
A WebmasterWorld thread has two webmasters questioning the data, one wrote:
It seems to me they only count their own clicks or their webmaster tools is broken completely.The numbers don't add up at all.
It is honestly rare to see people talk much about Bing Webmaster Tools or Yahoo or Bing at all on the SEO front, so when I see something like this I ask questions. Go check your analytics, compare it to Bing Webmaster Tools and let us know here or in the thread.
Truth is, most webmaster tools analytics never match up with normal analytics. But it should be clear if Yahoo is completely missing for larger sites.
Forum discussion at WebmasterWorld.