Originally Posted by Adraco

Mutt,
It works like this.
1. Create an advertising spot.
1.1 Create a campaign to run in that advertising spot.
1.2 Create/upload the banners which will belong to that campaign.
You can then assign certain weight/priority to the banners in which will be shown the most often.
You can also have like a Friday campaign, that has its own set of banners and you only activate the Friday campaign for those Friday nights.
It can most certainly show site A's banner more often as all the other 15 in your example above.

Yes, it handles flash .swf files and iframe ads.
For some of my sites, I run juicyads for the time being, and I run those iframes from juicy directly as banners in Smart Spots.

I really recommend getting it, for a very good price you get a lot of functions. Make sure to set it up with a memcache, because that will make serving the ads go a lot quicker and a regular user won't notice any difference at all.