Microsoft announced today that it is making some ad relevance improvements, namely, a temporary increase in Bing crawl rates. The adCenter team writes:

Along with our consistent efforts to increase relevance for your adCenter campaigns, we will be temporarily increasing the rate at which your sites will be crawled to 20 to 30qps. This is within the accepted standards for crawl rates, and is vital to continuing to provide the most relevant advertising experience possible.

The team adds that if you have any concerns with the increased rate, you should contact your account management team as soon as possible. Microsoft's Tina Kelleher adds that you can also leave comments on this blog post.

Keep in mind that Bing results have overtaken Yahoo results now in the U.S. and Canada, and the companies have begun testing the adCenter transition for pad results.

Last week, Microsoft announced that it has expanded negative keyword limits for adCenter, so advertisers can now add thousands of negative keywords.