The problem is that TripAdvisor must be careful as it tries to develop new income sources separate from what it gets from the two market leaders. ­Looking at the company's revenue by product, you do see a good, rising revenue trend, roughly doubling in the past four years. Excellent. Investors can notice about 80% of the revenue comes from ads, 69% click-based and the other 10% from display. There's nothing wrong with that. That's actually why the company has been as successful as it is. Viewers come for the extensive reviews and holiday ideas, and TripAdvisor gets revenue for ads and referrals. Like many others, I myself have used the site to find interesting locations and good restaurants, and it is helpful because I get the viewpoint of fellow travelers and diners. That said, about 46% of total revenue was generated from Priceline and Expedia business around the end of 2014. That becomes a problem that all business students should recognize - having too much of your revenue coming from but a few clients or businesses. Adding on new revenue sources is what a healthy, growing company needs to do. Still, Priceline and Expedia could put pressure on TripAdvisor and competition can become expensive. Get the full story at Seeking Alpha