This is what it took 2 fucking weeks to find out had boned my account. From their email:
I have sent your escalation to our engineers and they have found that your ad delivery has dropped off due to significant relevancy/quality issues (then they give an example that applied to ONE ad out of hundreds, grrr)
I have added some of our information on Quality-Based Ranking.
Quality-Based Ranking (QBR) is part of the adCenter quality initiative and is designed to carefully assess the quality and relevance of an ad and landing page to a Bing user's query, to ensure the best experience for the user and a better marketplace for our advertisers. Our QBR formula determines quality and relevance by assessing:
· Bidded keywords
· Ad copy: Ad titles, text, and display URLs
· Landing page
· User experience
What to Expect
· An improvement in the experience that Bing users have with sponsored listings.
· If your keyword, ad, and landing page combinations are of low quality or relevance based on the QBR criteria we have specified, you may notice a decrease in impressions and clicks to your site. Like other online advertising programs, in order for your ads to perform consistently, you will need to improve the quality and relevance of your advertisements. You may also need to adjust your default keyword bids (maximum cost-per-click) to remain in the same position that you were in before.
How QBR Benefits You
· Advertiser Benefit: Better Marketplace
Advertisers with high quality keyword, ad, and landing page combinations will benefit by an increased likelihood of achieving a higher ranking ad and higher click-through rates.
· Customer Benefits: Better Relevance
o Provides Bing users with ads and landing pages that are most relevant to their search queries.
o Improves the experience for Bing users, thereby increasing engagement (in terms of number of searches per searcher) and the likelihood of clicks on ads.