US tech giant Amazon says that it has deleted more than 200 million fake product reviews from its websites worldwide in the past year as part of efforts to prevent and detect fraud and manipulation.

Amazon says that it's also increasingly taking legal action against companies that sell false or fictitious reviews, and is filing dozens of lawsuits in different countries to this end.

Considerably more false reviews were deleted in 2020 than just a few years ago, according to Amazon. The Seattle-based company says that it now spends US$700mil a year worldwide on employees and software dedicated to preventing and detecting this type of activity.

The tech giant founded by Jeff Bezos by isn't the only company cracking down on fake reviews. Sites that specialize in travel bookings, for example, have had issues with falsified hotel reviews.

So does all this mean it's finally safe to trust reviews on Amazon?

Not blindly, according to experts. Glowing recommendations for a product or service may encourage you to try it out yourself, but consumer advocates say it's difficult for consumers to work out which reviews are genuine and which ones are not.

Meanwhile civil lawsuits against agencies that peddle falsified reviews can be difficult because they often operate from abroad, meaning Amazon will likely need to continue its whack-a-mole approach of deleting steady numbers of fake reviews in future.

Generally speaking, the more reviews a product or service has, the likelier it is that you'll find some sincere ones.

It's important to put individual reviewers under the microscope, says Tatjana Halm, a consumer advice specialist in Germany. Some people post a lot of online reviews. If someone is reviewing lots of shops and restaurants in different places over a short timespan, that could be an indication of a fake review.

You should also be suspicious if a large number of negative reviews are followed by a few positive ones. That could be a non-neutral party actively trying to balance out the bad reviews with good ones, the consumer advocate says.

There are also manufacturers, service providers and websites that reward customers or users with coupons if they give positive reviews. Such manipulative practices mean the reviews can't be trusted, Halm says.

"You should look at different platforms and draw comparisons," she advises. It's also useful to know who is allowed to post a review. A verified review means that only genuine customers or buyers are permitted to leave one.

Ultimately, however, it remains questionable whether online reviews can offer a representative and trustworthy picture of a product or service. "In the final analysis, you always have to be suspicious," Halm says.

 - dpa