I\'m making an application that retrieve tweets on Twitter of a user.
Those feeds contains links to external resources, such as Artciles, Webpage or YouTube video.
These og:
attributes are Open Graph Protocol attributes, there are many way to get these datas : you should check the codes of Open Graph Protocol parser which may be very usefull for you, and this PHP and jQuery Facebook link parser.
You can also check this StackOverflow Question about PHP parsing and this Opengraph PHP parser and dynamically use them with ajax calls.
Finally, this StackOverflow question about JQuery and pure JavaScript parsing is very interesting and could really help you.
Hope you'll find what you need ! ;)