(Image Credit: iTunes App Store)

Saying "Yo" is now a big deal.

A new messaging app called - you guessed it - Yo, has become an overnight sensation, quadrupling its number of users in the past day to 200,000, according to the app's Twitter account.

The premise is simple.

Choose a user name, type in your mobile number, find friends and you're ready to "yo."

According to the app's creators, the right "Yo," which happens with just one tap, is all about the recipient and timing.

Sometimes that means sending a good morning "Yo" to a friend.

Thinking about your boyfriend? "Yo" him.

Finished a meeting and ready for a client to come by your office? "Yo," will do the job.

The app is available in the Apple and Google Play stores for free.

The app keeps tracks of the "Yo's" you receive from friends.

So what are you waiting for? Get yo-ing!