The answer to the crossword clue "What puts the 'i' in Silicon Valley?" is "APPLE." This clue is a clever play on words referencing Apple Inc., a well- known tech company based in Silicon Valley. The phrase "puts the 'i' in" figuratively alludes to Apple's popular product naming convention using the prefix "i" (such as iPhone, iPad, iMac, iPod) rather than the literal spelling of Silicon Valley. So, in the context of the crossword, "APPLE" is the answer that metaphorically "puts the 'i' in Silicon Valley" through its iconic i-products.