white label design strategy

I have a data driven web site written in asp.net. I've had 3rd parties contact me and ask if I could provide branded access to their own users. I think this is definitely the direction I want to take the site, but I'm unsure of the best way to get this done. I'm looking to get some input on various ways to implement this, and some pros and cons of each method.

I'm looking to put as little technical burden on the 3rd party as possible. Hopefully I can just provide them with an html snippet, and that would be all it takes to do the integration.

Here are a few ways I've come up with to make this happen. Please comment on the wisdom of each, and provide alternatives if you think they are viable:

• Create a subdomain for the 3rd party. Read that from server variables and set theme and data accordingly. Provide a link to 3rd party web master.
• Create a redirecting page i.e. http://MywebApp.com/landingpage?ClientID=xxxx. Page takes xxxx and writes into session, then that is used to set themes and data. Similar to above
• Work within an IFRAME in the 3rd parties site.
• Provider Javascript code to 3rd party's web master to dynamically generate content on their website, originating from our servers. I'm not even sure how开发者_高级运维 to do this, but I see providers like Disqus and facebook use this approach.

I'm facing a similar choice now, although with the requirement of customer top level domain (e.g. company.com.) I'm leaning toward the IFRAME as it provides maximum customizability (they can run on whatever domain they want and frame the content - from widget sized to full page) and less work on our end. This strategy seems to work quite well for facebook both on canvas and for widgets.