Why is surfing popular?
It's a popular sport that many people enjoy. Their reasons for liking it could vary from it's fun to it's a great way to stay in shape. Basically, it's popular because many people like it. Most people surf for the fun of it and that people like to compete against others and think that if you surf the ladies will like you more.
It largely depends on your purpose for going. For example, if you are a man looking for lots of female companionship or a very interesting nightlife, then Pattaya (Chonburi) or Patong Beach (Phuket) are very popular destinations. If you are into kite surfing, then Hua Hin or Thung Wua Laen Beach, Chumphon are popular destinations. Rawai and Chalong (Phuket) also have some limited kite surfing options.
No, Tampa is not a great surf area. During hurricanes (when you shouldn't really be out there) some surfable swells do come up. Skimboarding is a much more popular water sport in the Tampa area. If you are looking for surfing, it is better to head over to the other coast. Areas like Cocoa Beach are better known for their surfing conditions.