Silicon Valley's press corps is wringing its collective hands over the botched launch of Cuil, a Web search engine. Instead of complaining about Cuil's piss-poor search results, why is no one asking who paid for this debacle? The surprising answer: Wal-Mart.More precisely, Wal-Mart family money. Madrone Capital Partners, which manages venture-capital investments for the heirs of Wal-Mart founder Sam Walton, led Cuil's most recent $25 million financing round in April. Madrone's Greg Penner, who married Carrie Walton, Sam Walton's granddaughter, is on Cuil's board. And on Wal-Mart's. Penner, who lives in Atherton, has ensconced himself in Silicon Valley society, despite an atypical background for the liberal Bay Area: His parents are evangelical sex therapists who believe in counseling gays into heterosexuality. He is a protege of Stanford Business School's Jack McDonald, and served as an executive at Walmart.com, a short-lived dotcom spinoff of Wal-Mart backed by Accel Partners and later folded back into the retailing giant. Most significantly, he's also a board member of Baidu, a Chinese search engine which is eating Google's lunch in that country. The Waltons' investment in Cuil could be written off as simply an attempt to make money. But with Penner involved in two prominent Google's rivals, it's hard not to wonder if the Bentonville gang isn't hoping to do more than just add to its pile.