Perhaps there's another factor - appendectomie$ are a large source of income, often done "while we're in there" during unrelated abdominal surgery.  Would people still go for this if they knew the appendix served a useful function?

The article itself also claims that appendectomies have no negative side effects.  This is a bizarre conclusion, given that it's known they're associated with an increased incidence of Crohn's disease - a debilitating disorder of the gut - years, even decades, after the surgery.

Most strangely, they claim that today's world no longer needs this reserve of good bacteria.  Yes, cholera & dysentery are gone, but did they forget to consider antibiotics, salmonella & e. coli outbreaks, and rampant antibacterial products that prevent us from the regular, natural replenishing of bacteria we are supposed to get from our natural environment?  Other regular disrupters of gut flora are hormonal contraception, heavy metal contamination (in water, vaccines, fish, fillings,...), water chlorination (intended to kill bacteria), sugar, & processed food.

This is a good example of how to glean facts from mainstream articles - the facts about the appendix are priceless; the conclusions are ... well, you decide.

Further items to ponder:

• If this is the appendix's role, and given that the appendicitis rate has fallen in the last hundred years, then perhaps we can prevent appendicitis by the same good habits that promote good intestinal flora?  That is, eating only real food (nothing processed) and avoiding sugar (and artificial sweeteners) like the plague.
• Ah, fascinating, this article says appendicitis is usually caused by blockage of the appendix's outlet - by fecal matter or lymph nodes enlarged by viral infection.  So normal good health practices should dramatically reduce the likelihood - see above point.  Also, this means that perhaps there are other steps that would be more appropriate than cutting it off now that we know it has a function - like removing the mass, or medical/nutritional steps to remove the viral infection?
  
• We should probably be extra cautious when advised to remove it - double check the big three (confirmed here, as well as the link in the bullet above): pain that starts in the belly button but moves to the lower right, total loss of appetite (even favorite foods), and massive pain if you jump hard.  Women, especially, benefit from pre-operative CT or ultrasound scans to determine if it's really appendicitis.  (Is that b/c of confusing reproductive pain for appendix pain?)
• What other surgeries are not always necessary; what other body parts aren't really "useless?"  Tonsillectomies and adenoidectomies are already just a fraction of what they used to be; what about our wanton removal of gall bladders, uteruses, postmenopausal ovaries, & wisdom teeth?  Ought we maybe to consider they serve a purpose and try methods that solve the root problem w/o extracting them, first?  Prevention, even?

I'm much indebted to Dr. Mercola's article for the links that spurred this blog post!  According to some commenters on the article, this Anatomy book stated 10 years ago that the appendix "plays an important role in bodily immunity," and Ayurvedic medicine has long recognized the appendix as a reservoir for beneficial bacteria.  Why does it always seem to take at least a decade for real findings to make the headlines?