Most new online businesses are small operations, with little budget, often slim previous experience, and high hopes. Many fail not for lack of a good idea, but for lack of administration and financial outlook. A typical example is the business that gets lots of customers, makes lots of sales, and does not have the ability to fulfill each order, deal with customer service issues, and respond to anything in a timely manner. Why? Because they were not prepared. They did not have the staff to deal with all the issues that are easily foreseeable. In a sense, it is getting too many customers that kills a good deal of businesses.
Patents are worth getting if you have an invention or novel process you want to protect. You would surprised at the types of things people have attempted (and succeeded) at patenting. One of my favorites was something similar to "method for exercising your cat," which essentially involved using a laser pointer to attract your cat's attention and exercise the cat while it chased the red dot around. This was an instance were a patent was issued, but later it failed due to the obvious factor. The patent examiners at the USPTO are not always the last word.