You can host a Silverlight app in HTML using the <object>
tag, there is no need for the blog host to understand any of this. There is no server side element to hosting a Silverlight app its a purely client side thing.
<object id="SL" data="data:application/x-silverlight-2," type="application/x-silverlight-2" style="width:400px; height:300px">
<param name="source" value="MySLApp.xap" />
<param name="minRuntimeVersion" value="3.0.40624.0 />
<param name="initParams" value="someParam=value" />
<a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=3.0.40624.0" style="text-decoration: none;">
<img src="http://go.microsoft.com/fwlink/?LinkId=108181" style="border-style: none" alt="Get Microsoft Silverlight" />
</a>
</object>
In this case the Silverlight app "MySLApp.xap" is placed in the same folder as the HTML page using it. However it could be on a different server if you like. However access to the HTML Bridge will be blocked but then if your app is self contained and does not need to communicate with the host page then there is no problem.