[thijsc]

You could implement it as an API call. The site could fetch the current "sponsored by X" line and render it directly in the HTML it serves.

[jasonkostempski]

But I don't want to point my servers at shady URLs to fetch random content, that's what the users machines are for.

[thijsc]

Well the premise is that you would trust the company you choose do business with for this service.