Again, find an interesting fossil, and the media is full of hyperbole.
Ardi is probably not a human ancestor. Ardi is probably not a common ancestor of humans and chimps.
The hominin family tree is very bushy. There's lots of "cousins" in it.
It's much more likely that Ardi's species is a close relative of a human ancestor than a direct human ancestor - but Ardi is probably very like a direct human ancestor that lived at the same time (a bit like looking for Cro Magnon and finding Neanderthal - it's really a very good approximation). It's even less likely that Ardi is the most recent common ancestor of humans, chimpanzees and bonobos. Again, Ardi is probably somewhat like that common ancestor, but to my understanding the branch point is a good deal older than Ardi - the figure I usually see is 6-7 mya, Ardipithecus ramidus is a bit over 4.
You don't need to call your great aunt "grandma" to feel close to her.
The fossil is a very exciting find. We don't need to make it something it's likely not, for it to be fascinating.
(been trying to post this since news first came, but haven't been able to get on blogger for some reason)