It wasn't long ago that Facebook rolled out their commenting system to off-Facebook publishers. They then enabled @ tagging within Facebook comments. And now it appears that they are enabling more robust content creation / sharing (ala the normal "status" update box). Here is an example where I commented with a URL and it expanded it into a full "link" treatment: image, summary, hyperlink, etc. You can also see that I referenced a Facebook page using the @ sign and it auto-linked it:

Of course, if you're interested in seeing the page I was linking to - it's!