Voyeurism drives a lot of our activities online. Admit it -- you've definitely googled or facebooked an old friend with no intention of reconnecting. You just wanted to peer into their lifestream. Venture Capitalist Michael Eisenberg told me once that many of today's successful online businesses are winners because they incorporate some level of voyeurism. If investing is about learning, we're always interested in what others are doing, but sometimes it's hard to figure out. To see what a large asset manager is doing, we can check public portfolio filings. Other times, we pick up what others are investing in over a game of pickup basketball. Regardless of how we get this information, we place a value on it (sometimes, even a value greater than our own opinions). The collective tradestream (and dissemination tools like StockTwits and SeekingAlpha) allows us to drop in on the investing party our friends are having -- at any time. Not only can we get ringside seats into smart investors' every activities, but we get their rationales for doing so. It's pure learning -- both cognitive and the emotion set behind the trade.