TikTok is now the number one app in the U.S. surpassing the likes of Facebook, Twitter, YouTube, and Instagram. It has been downloaded for millions of times and used by young people, teens, and even kids today. But what does this app has that turns it into the latest craze in digital media?

TikTok is a Chinese video sharing lip-syncing app. Its users can create a 15-second clip using different tools, like overlaying a song or movie dialogues that they can act and sing to. It also has animations and editing tools.

According to Softonic, TikTok replaced Musical.ly. The Chinese firm Bytedance gave it a fresh look and new name when it acquired the app in 2017. Since then, it managed to have 500 million monthly users in over 150 countries worldwide.

Talking about TikTok, App Annie markets insights manager Lexi Sydow said that gaming and social apps come and go today. "[They] come in very quickly and leave that kind of flash in the pan," she told CNBC.

Sydow explained that part of the social networking app's appeal is the network effect. The more family and friends the users can get on the app, the more benefits they can have, and it gradually increases.

TikTok successfully obtains its status with the help of Jimmy Fallon. The 44-year-old host launched the tumbleweed challenge on "The Tonight Show starring Jimmy Fallon," and it quickly went viral.

Jimmy Fallon instructed the TikTok users to choose the song the show created for the challenge and film themselves rolling on the floor like tumbleweed. A lot of people get interested and take on the challenge.

The South China Morning Post reported that TikTok now becomes a "unique cultural gathering place." Here, teens and young people take challenges, play a game, and reveal their visual styles.

Users can also discover new communities on TikTok, and make their memes and video, which have the possibility to go viral. It seems to contain Facebook and Vine's, when it was still famous, contents in one app. It, too, may be the reason behind Facebook's new feature, called Lasso, a TikTok clone.

TikTok contains a collection of endless videos that users can search and view. The app can even recommend a clip that users may have the interest to watch based on their viewers' history.  It also advised its users to take a break if they continuously browse the app for about two hours. Although "cringe" edits are now taking the scene, what important today is it is giving fun and entertainment to its users.