This kind of mutation has probably occurred many times in many different species, but because of its unique chemical environment, this bacteria is the only one that actually gained an advantage from it and retained it. It's interesting, but nothing that justifies the suspense NASA tried to build for it.
The only one thing I find odd about current science and the search for life (ie:SETI) is the presumption that other forms of life out their would use radio waves to communicate, just because we haven't broken past this barrier yet doesn't mean that other life forms haven't either. They may use some other currently unknown to us form of communication that we have yet to even dream of... Just a thought... 
The other odd thing about it is that SETI would likely only detect analog broadcasts. Digital radio broadcasts are practically indistinguishable from static.
Human civilization will stop using analog communications in the very near future, so even if aliens are in fact following a similar technological path to our own, they might only be using detectable radio signals for a century or so. That's a pretty small window of opportunity for us to detect their signals.
