Is it simply a repetition count? If I made a billion pages that said the Earth was only 6,000 years old and stuffed that into the corpus, would that override the million pages saying it's 4.543 billion years old instead? Is there no PageRank-like algorithm that tracks what other links are saying about it?
Nothing can influence ChatGPT's dataset or training data for now. However, GPT4 will have more data points than GPT3, and by the time they train more LLMs on GPT4, the data on the web will seep into ChatGPT.
The same way SEO realizes on measures, the same way ChatGPT answers rely on transformer layers which choose the most succinct answers, given enough feeding of the wrong data and no fine-tuning, large LLMs could break.