Refresh meta data in posted URL
In Facebook, when I post the link http://wisdomuniversity.org, Fascebook includes old metadata (Title, description, etc.). I recently added Open Graph Protocol meta tags, but Facebook still uses the old stuff. How does Facebook refresh this metadata and can I force a refresh?
Answer
You need to ping facebook and notify them to update changes and to do that you can use URL Linter. It may take some time for facebook to update your changes. I'm not sure how much time they take to update after pinging, but just try it.
EDIT: This is officially from facebook: Open Graph protocol
Editing Meta Tags
You can update the attributes of your page by updating your page's tags. Note that og:title and og:type are only editable initially - after your page receives 50 likes the title becomes fixed, and after your page receives 10,000 likes the type becomes fixed. These properties are fixed to avoid surprising users who have liked the page already. Changing the title or type tags after these limits are reached does nothing, your page retains the original title and type.
For the changes to be reflected on Facebook, you must force your page to be scraped. The page is scraped when an admin for the page clicks the Like button or when the URL is entered into the Facebook URL Linter. You can programmatically force your page to be scraped by cURL'ing the linter. For example:
curl
> https://developers.facebook.com/tools/lint/?url={YOUR_URL}&format=json