Twitter's (NYSE: TWTR) big day is making Twitter shareholders very happy, and some S&P 500 investors very nervous. In this episode of MarketFoolery, host Mac Greer and analysts David Kretzmann and Matt Argersinger explain why the S&P's massive weighting in tech isn't as alarming as it first seems, and what other funds and ETFs investors can research for more diversified market exposure.Also, they hit on a few of the market's biggest news items: how this S&P business will affect Twitter's long-term future, what it means for Starbucks (NASDAQ: SBUX) that Chairman Howard Schultz is finally stepping away from the business, and why the unsexy, unloved banking sector is one that long-term investors won't want to miss.A full transcript follows the video.Continue reading