It's been a bit of a cyber adventure making cross origin content work.

What that means is that people can host their own content on their own site, but still thread it in the discussions here. It's between the client browser and the service that hosts it and does not transit mine: If Google can link it then so can I. I will be able to support filtering (which is under user control) but not flagging when it's not on my site.

Now it's simply a matter of adding a hosting field to the data base for each user (and use this one as the default).