Having finally had to enable embedding video into my blog postings, I found a way to configure Community Server to do so. Community Server has a 2 layer subsystem for stripping out tags.One subsystem is in the communityserver.config, and another subsystem is in the editor itself.

Edit communityserver.config and add the following tags into the html section within the Markup section.

<object classid="true" codebase="true" WIDTH="true" HEIGHT="true" ALIGN="true" VIEWASTEXT="true" id="true"/>
<param name="true" value="true" />
<embed base="true" wmode="true" name="true" allowScriptAccess="true" src="true" quality="true" scale="true" style="true" bgcolor="true" width="true" height="true" align="true" type="true" pluginspage="true" />


Also, modify tiny_mce.js located under Web\tiny_mce\scripts\tiny_mce and locate the following Javascript statement:

this._def("valid_elements", "xxxxxx"

add the following (let's call it YYYY):

+object[width|height],+embed[base|wmode|name|allowScriptAccess|src|quality|scale|style|bgcolor|width|height|align|type|pluginspage],+param[name|value]

such that the Javascript statement becomes

 this._def("valid_elements", "YYYY,xxxxxx"