International Style Jive
This style is the most commonly taught style in Latin - American / Ballroom dance schools in Europe as it would be included in medal tests. In America, this style is also known as "East Coast Swing".
Rock & Roll
Swing bands tended to be very large, so, after the 2nd World war, people couldn't afford to pay for big bands any more whilst they had to spend their money on rebuilding etc. Rock & Roll music replaced swing, so the danced developed into something more like the following clip. Whoever posted the following 2 clips was mistaken when they called them Rockabilly which is a much faster rhythm.
Nowadays, social Rock & Roll would normally be danced as shown in the following clip which includes a lesson. This is authentic Rock & Roll music too, not Rockabilly.
In a Rock & Roll club, people would normally "Bop" to Rockabilly music which is a solo dance as this would be too fast to dance in couples. One could equally well dance the American Country/Western 2-Step or the Quickstep. It seems that the word "Bop" is now also being used to include various other dance movements such as in Hip Hop.
The video clip below shows an International style Rock & Roll competition. Some would argue that the music is too modern to be genuine Rock & Roll. it would be far too dangerous to dance like this socially, but it makes an entertaining performance.
Modern Jive (Alias French Jive, Leroc or Ceroc)
The video clip above left shows an example of Modern Jive. When Rock & Roll was taken to France, The French called it Le Roc. As the music changed to slower pop music, the dance altered slightly. When Le Roc was brought back to the UK, it changed slightly again & was rebranded as French Jive, Le Roc & Ceroc. Ceroc is the most commonly used name for Modern Jive nowadays, but it is actually a franchise organisation with a huge number of members rather than a dance.
This style is a very popular style as it is the easiest to learn & the least technical of all Jive styles & can incorporate moves from any other Jive style plus Latin American moves. It has far less rules with no particular timing nor footwork. If you don't know your left from your right, but want to learn moves very quickly, then this style is for you, but don't be surprised if you still can't do anything else. The best Cerocers can usually dance some other dances or at least other styles of Jive too.