The 37-year-old Argentine runs the HouseFresh website with her husband, and they had been building a healthy niche in product reviews for air purifiers since 2020.

There were no ads, no product placements and no soft-pedalling -- if a product was bad, the site's reviewers would say so.

They earned commissions from clickthroughs to Amazon.

But Google's update changed all of that.

"We found that we went from ranking number one -- because we were one of the only people who had actually done a review -- to not even showing up," she told AFP.

HouseFresh used to get around 4,000 referrals from Google search a day, but this has since collapsed to around 200.

The dropoff in business has been so bad that Navarro said she had been advised to shutter the site and start over with a new domain name.

- Updates 'helpful' -

Underpinning the frustration for Navarro and many other sites is the lack of clarity over how Google ranks results.

The US firm is notoriously secretive about its algorithms -- so much so that an entire industry known as "search engine optimisation" has grown up trying to game the algorithm to get more clicks.

The latest update sent SEO experts into a tailspin, desperately trying to unpack why some sites were boosted and others getting downranked.

Google told AFP in an email that its update was designed specifically to give users "fewer results that feel made for search engines".

"The only changes we launch are ones that our experiments have shown will meaningfully improve results for people. And we do believe that these updates have been helpful," Google said.

Yet Navarro showed in a widely shared blog post in May that people searching for product reviews were increasingly being fed ads and content that appeared to be AI-generated or SEO-maximised.

- 'Tough market' -

Other material boosted by Google's update included user-generated content from websites like Reddit and Quora.

Google defended this approach saying "people often want to learn from others' experiences", adding: "We conduct rigorous testing to ensure results are helpful and high quality."

But staff at one European news website said their articles were now being routinely outranked by largely irrelevant content from Reddit.

The site publisher, who asked for anonymity because of the sensitive nature of the topic, said referrals from Google had plummeted by between 20 to 30 percent since the update -- and cutbacks would be inevitable.

"In an already tough market this is a serious problem for independent publishers like us," they said.

All the businesses AFP talked to said they were now urgently seeking ways to avoid relying on Google search -- whether by writing newsletters, making podcasts or finding other ways to attract audiences.

The boss of a fintech news outlet, who spoke to AFP anonymously fearing adverse effects on their business, said their competitors all employed SEO firms "to buy traffic".

"We don't do that but it's getting harder to hold that position as those sites didn't fall anywhere near as much as ours after this Google update," they said.

Navarro, who has had to reduce her staff drastically, has pivoted to video reviews and newsletters to try to reconnect with her audience.

And despite her experience with Google, she remains an optimist about the web.

She has been heartened by the many messages of support, and an uptick in referrals from alternative search engines like DuckDuckGo.

"The entire knowledge of humankind is on the web -- and that's worth something," she said.

"I don't want to give up on it just because Google is broken."