Made-Up Concept Got Cited by AI Search Within a Week

Researchers at Fudan University posted a completely fabricated concept across several sites online, and 8 of 10 AI search tools tested cited it within a week. Search Engine Journal covered the paper on October 19. All four English-web tools tested, ChatGPT, Perplexity, Grok, and Google AI, were among the eight.

The team first identified, for each tool, its most-cited sites that allow ordinary users to post content, narrowing the list to nine sites including Medium, YouTube, and the Chinese platform Sohu. They then invented a nonexistent concept called the "Cactus Gravity Protocol," drafted posts about it with ChatGPT, revised them by hand, and published them across those sites.

Running the same questions through all 10 tools daily for a week, the share of answers linking to the planted posts varied sharply by tool: Grok cited them in 30 of 32 answers, Google AI in 15 of 33, Perplexity in 13 of 35, and ChatGPT in 7 of 20.

Fabricated details were repeated in answers at different rates too. Grok reproduced them in 53% of its answers, ChatGPT in 10%, and Google AI in 6%. Perplexity never reproduced a single planted detail.

The researchers also found that where content was posted mattered more than how much was posted. A single post on a frequently cited site drew a citation quickly, while 40 posts on a self-hosted WordPress site drew zero citations over the week.

On Sohu, the team varied the number of posts per topic from 1 to 20, and total citations rose from 24 to 128. Since each volume level used a different topic, the researchers treated this as an association rather than direct proof that volume alone drives citations.

The team also bought a $14 posting package from a Chinese GEO vendor. All 13 purchased posts went live within 28 minutes, and one was cited with a fabricated detail by the Chinese AI search tool Doubao within an hour.

The researchers noted that because every topic tested was fictional, it's unclear whether the same pattern holds for real brand or product searches. The tests ran between March and April of this year, and the team said it notified all 10 platforms of its findings.

In Korea

The results suggest that posting on one site AI tools already cite often is more likely to lead to citation than spreading content across many sites. It may be worth revisiting how you choose where to publish.

Source: Search Engine Journal, October 19, 2026. Checked October 22, 2026. Read the original