AI search engine Perplexity is in fundraising talks and aims to raise $500 million at an $8 billion valuation.This would more than double Perplexity's previous valuation of $3 billion.Perplexity currently receives about 15 million queries a day and generates approximately $50 million in annual revenue.Despite facing accusations of unauthorized web scraping and plagiarism, Perplexity's CEO expresses a desire to collaborate with publishers.