Look at the address bar above. Notice it starts with https:// Some web pages understand what https:// and http:// and WWW means. But there are pages that need to use their own special coding. Contact support for that site,

Edit: Actually, the below setting may not be necessary for the status/post box.

Usually Facebook will detect the links and insert content from the page in a box. I'm sure you've seen that in other posts. When I tested just now, it happened in real time in the "post" box, but in a comment box, only after I submitted the comment.

In order for Facebook to do its real-time magic, you need at least one Firefox setting to have its default value:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste clip and pause while the list is filtered

(3) If the dom.event.clipboardevents.enabled preference is bolded and "user set" to false, double-click it to restore the default value of true

Some users have switched that setting because they weren't able to paste into YouTube comments. There are other workarounds for the YouTube paste blockage. For example, see: https://support.mozilla.org/questions/1089360#answer-807728

Was that the problem?