Multi-Site or Virtual Domain Comparability Jomsocial

Christopher,
I'm honestly not fully sure what you're asking. It seems you asked a question to someone else (JomSocial developers?) and you provided their response here.. but without the original question, it's kinda difficult to understand what you're looking for.

From what I can tell, you're asking about how to use JFBConnect on multiple domains. If so, there's a lot more we'd need to know, but I'll answer as best I can...
Many social networks will only work on specific domains you setup in your Application. Some social networks only let you use their application on one domain. Others let you specify multiple domains.
Facebook does allow you to setup multiple domains. You'd do so by adding each of the domains to the 'App Domains' field. Then, in the Valid Redirect URIs, you'd follow step 21 in our Facebook Application Setup Guide to set the URL from every domain that the app may be used from.

In general, we don't recommend using multiple domains for one site. It causes confusion for users, multiple extensions have issues with it and each social network has their own limitations. For social networks in particular, those limitations change frequently. Facebook, for instance, did not allow multiple domains with the same app for some time and I wouldn't be surprised if they removed that ability in the future.

If possible, I'd recommend redirecting secondary domains to the primary one you want to use. For instance, fb.com redirects to facebook.com.. you can't navigate or use fb.com on it's own.

I hope that helps, but again, if you can give us more details of what you're trying to do, that would help.

Thanks,
Alex

JFBConnect *should* work in those situations, but we've never tested with MightySites and are unsure of any other users that chose to use it. Some notes that you will need to be aware of:
* Some social networks allow their application ID to only be used for one domain. We can't get around this.
* JFBConnect only allows one set of API keys for each social network. I'm unsure if MightySites lets you set multiple configurations for different extensions. If you need multiple API keys (to allow social networks to work on multiple domains) this will likely not work.

There are probably other issues you will encounter as well that I can't even think of right now, but the best way to find out the issues is simply to try. We test with many extensions and have had experience debugging issues with many others, but your use case is unique and I just can't tell you 100% one way or another what issues (if any) you'll run into.

Please keep us posted with your testing and what you encounter. We'll help however we can.

Thanks,
Alex