To the casual observer, it seems like American society gets more litigious with every passing year … with legal judgments handed down in cases that might have seemed totally frivolous in earlier decades.

But one area where the courts don’t appear to be favoring plaintiffs at all is in the realm of Internet defamation lawsuits. No matter how many times someone brings a legal action – and with all sorts of corroborating evidence in hand — the cases are thrown out of court.

The most recent example of this comes from the 9th Circuit Court of Appeals, which has just ruled in favor of Google in a lawsuit involving a family-owned roofing and construction business. The owners of the business had sued Google for defamation, citing an anonymous post that appeared on Google Places.

The anonymous poster claimed that “this company says it will fix my roof, but all I get are excuses.” According to the suit, this post has hurt business prospects, but it’s been impossible for the company to attempt to resolve the customer’s problem due to the anonymous nature of the post – or even to confirm that it represents an actual customer’s experience.

And I don’t doubt at all that business has suffered for this company as a result of the negative review. Results from a new survey conducted by Cone Communications reveals that ~80% of consumers have changed their minds about purchasing a product or service based solely on negative information they encountered online. That percentage is up from ~67% in 2010.

Clearly, online information has more power than ever to “make or break” a product or service these days.

But the appellate court sided with the district court that had ruled earlier that Google was immune from liability. The court wrote: “The district court properly dismissed plaintiffs’ action … because plaintiffs seek to impose liability on Google for content created by a third party.”

As in all the other cases it has successfully checkmated, Google moved to have the case dismissed on the grounds that the federal Communications Decency Act immunizes web sites for libel claims that stem from users’ comments.

I’ve blogged before about courts and the Internet, and it’s always the same: Trying to sue for “transgressions” carried out on the Internet is like banging your head against a wall.

The wall doesn’t budge, and all you end up with is a big headache.

So it bears repeating: If you’re thinking about bringing a legal action against someone because of an online issue, do yourself a favor. Don’t bother.