Unless you've been hiding under a rock for the past 2 weeks, you're well aware of MSN's move to Bing.com, and the full force advertising campaign that has followed. Bing's homepage seems to highlight additional search options outside of "web", such as "images", "video" and "shopping". Exploring the "shopping" section, I noticed that they seem to suggest a number of topical/seasonal ideas and products.
On the Shopping homepage, what happens when someone clicks on the link for "Beautiful bathing suits" under "Plus size summer fashion"? Answer - A Bing Shopping search is performed for the search query: "women's plus size swimwear".
Notice that MSN adCenter PPC ads are now visible, even though the user never queried that particular phrase.
As an advertiser, do I like the fact that my ads are appearing or not? On one hand, I'm almost guaranteed to receive more impressions, and likely clicks, since users don't have to type any query into a search box in order to see my ad. Instead, the user is prompted to shop for the category/product by Bing Shopping homepage suggestions. This however, could also be the very reason that I dislike these listings. If users were not actively searching for the category/product, one could argue that they may be less likely to convert. We'd possibly encounter increased traffic volume on lower quality buyers.
In general, I don't think the extra traffic will cause headaches from a PPC perspective. Most of the traffic should be relevant, and should hopefully increase the sales volume at the same ROI. However, I'd pay close attention to any general phrases, though, as they have the greatest danger for buyers who are early on in their purchasing decision. (ex. Under "Father's Day electronics" one of the results is "laptops")
Something to be mindful of!