Realty Income is already the biggest name in the net-lease REIT sector, but that won't stop it from getting even bigger. With a $47 billion market cap, Realty Income (O 0.70%) is a giant company relative to its next-closest peer, which is about a quarter of that size. A very real question for investors should be: What can a company that's already the 800-pound gorilla of the industry do from here? The answer is keep growing, and likely rewarding investors with more dividends. Here's why. What you are buying ...