I have always intended to allow XenForo-related services to be announced here on XenForo.com, as I think that forum software supports a large ecosystem, and the community benefits if there is a central repository of information, resources and services available. If the community would rather that they are restricted to particular forums, I think I'm happy with that.
I like the idea posted here of forums where only licensed members can post their announcements, this would deal with a lot of spammy advertising, and the fact that the service vendor had purchased a license would show a certain degree of buy-in on their part, which should impart some degree of confidence to those considering using the services of that vendor.
I'd also like to draw a distinction between XenForo related services and XenForo resources, such as styles, add-ons and graphics. These should remain in their current forums until we have our resources management system ready to deploy.