Many modern tech start-ups now achieve big success within their first five years, unlike in the past when it took much longer.They can also succeed by changing how products are used, such as with online streaming instead of DVDs.Successful start-ups don't always need new products -- they can improve access to existing ones (like Amazon).Free products help people share them with friends and family, allowing the business to grow quickly and cheaply.Many start-up businesses fail for several reasons.Businesses that don't invest in branding or don't have enough funds usually fail early.To be successful, companies should focus on easy access, using free content, creating needed products, and good timing.A better way is the freemium model -- offering some parts for free and charging for extra features.