The fear is that this flu catches on in East Asia, esp China, where it can become a "shake-n-bake" with the avian flu, giving it human-to-human transmissibility. That was the fear with the avian which measured sources believe has been around E Asia for quite a while, a case of look and you will find, but itself not a serious threat.
That said, it is most unlikely that mortality will approach that of the 1918 or even that of 1958 (?), given the systems that are in place. Still, if there should be a pandemic, there will be ugly decisions and scenes -- there isn't enough vaccine to go around, not even anti-virals, and rationing decisions will have to be made. For those of us who are older, or have very young children, not pleasant to contemplate, as priority will be given to health workers and security personnel. This has been pretty much acknowledged.
None of which does not mean that the media has not gone unnecessarily ballistic over this.