I will put a box of beer on it that this has been left out so oxwall team plugins like attachments will be made to do this

Like so many other things

will toss another box of beer if internal links would be rendered right (if you use a closed community where a 3rd party plugin can't do that job)

its all here
http://oembed.com/
if the api was fully implemented it will fix 90% of the problems