well i havent looked at the source code but my feeling is embedly was probably integrated into text area a bit better and various buttons,  but what im planning on doing is altering soon my text area and tinymce , in such a way that all urls are urlencoded and sent to iframely to be rendered in a post.   versus having to add via the link button. which isnt present in the post editor but is present in the timeline post editor form.   also  i have a lot of folks that just paste urls into the text area, so im working on tackling that aspect as well .