Why does Facebook's Open Graph protocol require an fb:admins or fb:app_id .. and what is the importance of this property?
I already answered on Facebook Dev Forum :
As described here : http://developers.facebook.com/docs/opengraph/
Your page will appear in the "Likes and Interests" section of the user's profile, and you have the ability to publish updates to the user
- Without this property you'll loose admin right on the Open Graph Facebook Page
- Yep, when users likes your website's page, it'll generate an Open Graph Facebook Page : When users will try to go on it (by cliking on publications, or searching), it will redirect to your website's page.
- To publish status updates to users news feed, create events, or add pictures related to this page.