Why are the results in Bing & Yahoo! so different?

I noticed earlier in the month that Bing was doing something major with their search results and looking at their results this morning – little has changed. I’m noticing less websites being returned with five pages being the maximum amount of pages the user can select from. So what is happening with Bing!?

Bing/Yahoo! may take up minimal market share in the UK compared with Google, however these results are not going to help improve the current percentage stake. If we look at (what is quite a popular search term due to the longest grand slam final ever contested) ‘Australian Open 2012’ – you can see completely irrelevant results for the tournament itself, focusing more so on the location ‘Australia’:

Bing results for Australian Open 2012

So we have an Australian Rugby website, the National Library of Australia website and Google Australia – hardly relevant useful results to find out information on the final between Novak Djokovic and Rafael Nadal. But if we take a look at the results on Yahoo! (which uses Bing’s search technology) you’ll see a very different set of results:

Yahoo! results for Australian open 2012

If we take a closer look at the fluctuation in results for say ‘Tennis News’, it is apparent there is something major going on behind the scenes:

Bing Fluctuations for Tennis News

Authoritative websites like ESPN.go.com and sports.yahoo.com are dropping from the top ten for no apparent reason (along with a whole host of other websites). So, to conclude, why is Bing now returning irrelevant results to the search query and why is there so much emphasis on the location (if present) in the query?