If you want to boost your online income, niche markets are your key to success. A marketing definition; niche markets are sub-categories of broader markets, and can be very profitable. The key to the high profitability of niche markets is their specificity or target market strategy. Niche topics for example, it's much easier to find and market to people who are interested in 1964 Ford Mustangs than it is to market to people who are interested in cars in general (or even Mustangs in general). Plus, the people who comprise your potential customers in niche markets are usually quite passionate about their chosen interest, and are ready to buy if you've got the right marketing message. So how can you find hot niche markets to boost your online income?