What is R&B, how is it different from pop?

srry but its been bothering me for a while, so stuff like old Britney spears songs (oops i did it again-hit me baby one more time) and new lady gaga songs (poker face..etc) r pop right?
can u give me examples of R&B plz D:

Answer on What is R&B, how is it different from pop?

R&B is singing usually done over smooth soulful beats. Sometimes R&B music can also be singing done over hip hop beats. Pop, however, isn't.

Rihanna is not an r&b, she is a pop artist. Yes, she has a few r&b songs, but she is considered a pop artist.

R&B artists such as Trey Songz, Mary J. Blige, The-Dream, and Keri Hilson are a few examples of r&b artists who tend to have hip hop beats.

R&B artists such as Sade, Alicia Keys, Boyz II Men, John Legend are a few examples of r&b artists who usually tend to have those soft-smooth, soulful beats.