Unless they've changed it, you'll have to use the FaceBook SDK to do anything more than post a URL. FB's intent support is bad.
Ah, yeah. I was talking about iOS in particular. Android intents are pretty sweet -- a couple the missing bits to make them great in my mind are
-- App discovery: tell me about apps that can use my content if I don't have any?
-- Action curation: What do users think are the best app for this action?
If there's a document viewer, it'll listen in for the file types it supports when you try to open a file (I think its a VIEW intent). It's all very impressive and very, very useful.