Say you come up with a novel idea where you can't get any protection through patents etc. Whats the best way to protect yourself from the competition that will arise after you? For example. there is a company called Panna (pannacooking.com) that offers video cooking recipes. Novel idea, but nothing prevents someone from doing the same thing I don't think. What would a company like this do to fend off and compete with new comers in the market.
The best defence is a strong offence. Said another way, the best companies don't spend too much time looking in the rear-view mirror, and instead focusing on the drive ahead. Most web and mobile businesses are not defensible by true I.P but rather speed of execution, great design, responsive and caring customer support and a relentless concern for the customer. In the case of the example you provided, content quality and regular and timely updates are also key competitive differentiators.