Last week, we reported on what appears to be more cloaking tests by Bing, where referrer data for websites are being spammed (by Microsoft) with fake data. There have been more and more complaints about this in the Bing forums.
A new thread sprung up in the Bing Forums where Brett Yount, program manager for Bing, said:
We are rolling out a new spider, so it is possible that might be causing your activity increase. If this is becoming more of a problem, please send me a mail at email@example.com with your domain name and "single word query complaint" in the subject line and I will investigate.
Clearly, Microsoft now has a name for this issue internally. They are calling this a "complaint" but more importantly, it might be isolated to single word queries. In our example last week, the single word in that case was "donate". In the new thread, it is "copper," plus other undisclosed terms, not specifically mentioned by webmasters.
There is no official explanation from Microsoft on this issue, as of yet.
Forum discussion at Bing Forums.