For example, on this page http://coolscifi.com/threads/the-amazing-adventures-of-captain-quasar.17952 the first post of the thread starts off using an 'img' tag to embed an image. The description & og:description value in the source is now...
<meta name="description" content="[IMG] Hey guys! Firstly, let me just state for the record, I don't want your money, I'm not here to get funded on kickstarter, I'm not here to beg for..." />
The problem with that is if do something like a Facebook 'Share' button that grabs the og:description value then it ends up like this...
By contrast it seems like some tags like 'quote' are being gracefully handled by including the quoted text by excluding the [quote] tag from appearing. This page http://awalkerbit.me/threads/constantine.1044/, for example, starts with a sentence followed by a quote. When looking at the source the description is...
<meta name="description" content="Another comic to TV/movie adaption is in the works, this time DC Comics' Constantine.Neil Marshall (The Descent) is set to direct NBC’s drama pilot..." />
Unfortunately it doesn't seem like Facebook allows you to change the description or thumbnail from the shared link so we are at the mercy of whatever the generated og:x tags are.
The request then would be gracefully remove tags like [img] & [attach] from the generated meta tags.