These people have millions of fans and followers. They are famous, and millions of people watch Flip or Flop. They are a household name to many people. They might not be the most famous people in the world, but they are definately reality tv starts and there are people who are following this story.
Tarek and Christina El Moussa are not truly famous. I believe they are successful business people with some notoriety via their television program, but I would not classify them as famous. In my opinion, for one to be famous would need more far reaching notoriety and for a longer period of time.
No, the stars of Flip and Flop are not truly famous. These days everyone gets their fifteen minutes of fame. That does not mean that they are truly famous. The television show that these two people are on will never be popular enough to make them truly famous. They are just more well known than other anonymous people.
Flip or Flop is not a widely popular show. It has a small audience that is only into that certain type of home building show. It would be a stretch to say that their separation is a significant event in Hollywood. A person is not truly famous until they are known outside the show they are on.