Satire is one of the truly unique literary elements in that, those who do it, do it well, and those who don't, don't touch it.
Satire is a method of commenting (or in many cases, complaining) about society, politics, leadership, or generally, anything affecting the public that doesn't make sense, in a darkly humorous, and often subtly offensive way. Satire has the ability to offend and tickle an audience at the same time. This is why it is so effective when done well. Satire is never executed without a clear message intended from the outset. Then, that message is delivered in a slightly less-clear package.
Typically, in order to take a serious subject and make a serious comment on it in a way that comes across with a note of humor, the author has to succeed in a couple of areas. He or she must be intelligent, well read and informed, and relevant. Finally, the author must be passionate about what he or she believes. When we think of satire in the classics, we think of Mark Twain, automatically. But even in our modern world, satire continues to thrive in television (with shows like Saturday Night Live and Family Guy) and in print (publications like The Onion).
It continues to be a small and elite club, both on the sides of those who do it and those who understand it. I don't believe satire is something that is practiced and mastered. I really believe it is something that is innate and then honed to perfection. This is the final reason it will continue to be effective, because it will never become commonplace nor cliche.
A distinct advantage for satire as social commentary is its ability to be attention-grabbing. Standard persuasive pieces seem predictable in their delivery because every sentence is used as support and becomes repetitive in their point, especially if the social commentary itself isn't ground-breaking. On the other hand, satire uses sarcasm and irony to help comment and is therefore oftentimes speaking on the opposite side of the issue. This is an approach that isn't taken by many (whether for fear that people won't understand or because of the higher complexity involved with penning satire), which lends itself to increasing freshness. Thus, it is easier to capture people's attention because it isn't something that has been constantly repeated and thereby beaten down. A prime example of this is "A Modest Proposal", an essay by Jonathan Swift. In it, Swift comments on poverty, but does so from the "logical" proposal that society eats babies. While somewhat repulsive, this method sticks in the minds of the audience members, showing how satire is incredibly effective in delivering social commentary.