(Embedding disabled, limit reached) <- I have no need to explain this, good sir.
Well, in a forum I helped run they seem to be caused by the auto embedding mod. and/or a Java script embedding function on Youtube itself, so it will display the video hyperlink but not the video on the forum thread. Otherwise the youtube poster may have disabled embed setting, so yet again only the youtube hyperlink will appear 8 times out of 10 this is the reason.
Hope this sheds some light on the matter.