Hi Jeff Weber,
Thank you for your interest in our CMS.
Here are the answers to your questions:
1. How easy/difficult is it to embed an existing Silverlight application onto a Sitefinity "page".
There is a special Asp.Net control which hosts your application in it. Then you can use the Asp.Net control as any other controls in Sitefinity - just drag and drop it on the page. Once you have the Silverlight application, you can use it in to time with Sitefinity. Here is an example with the <asp:Silverlight> control - http://forums.asp.net/t/1343281.aspx
2. Can I use Silverlight 3's Navigation/Deep Linking functionality within Sitefinity?
Yes, in the same way as the example shows in question 1.
3. How easy/difficult is it to put Adsense ads on my pages hosted within Sitefinity?
Let me know if you need any further information. I will be glad to help you.
the Telerik team