Microsoft reveals four areas of concern related to Windows Phone Marketplace

Microsoft limits a developer to the use of five keywords that help people find a certain app. Microsoft says any app with more than five keywords will have all of the keywords deleted. And the keywords need to be relevant to the app. In other words, you couldn't use a keyword like Skittles for an app that features a stopwatch.
Lastly, Microsoft spelled out its policy on content. The tech titan will not allow "sexually suggestive or provocative" images. Microsoft says that it will accept content like the type you would find on prime time television or in a magazine's swimsuit issue. Microsoft said it will start looking at the content, titles and icons of apps that are submitted and are looking for more "subtle and modest" imagery. And if you see an app that you think violates Microsoft's policies, you can report it to them via email at reportapp@microsoft.com. No one will call you a stool pigeon.
source: WindowsPhone via WPCentral