There are basically two contexts for dancing: social and performance. The dancers' attitude and focus is different for each context, and often the types of moves are different too. What's behind each context is the question "who is being entertained?".
When dancing socially I'm entertaining only two people (myself and my partner). Similarly, my partner is entertaining two people: herself and me. I entertain her by choosing moves that fit the music and her style (including her favourites, if I know them), and I also give her space to play. She entertains me by her style, plays, sabotages and overall attitude. This is a dance conversation. Other people around the dance floor may be entertained by our dancing, but that's incidental. When dancing, our focus is on each other, and we're only concerned about people as part of normal floorcraft.
As with a verbal conversation, some dance conversations are better than others. Followers can be bored by a leader who basically monologues - a one-side conversation with no room for interjection, particularly if it's heavy-handed and predictable. Leaders can be bored by followers who stay silent - simply following, without adding anything. Fortunately in social dancing we're rarely with the same dance partner for more than a few minutes, so by the time that we realise that we're bored with this person, it's time to move on to the next.
When there's a mismatch of experience, the conversation is almost certainly going to be one-sided - but there are compensations. An experienced lead with an inexperienced follow can enjoy showing off (much as a well-travelled person delights in telling an audience travel anecdotes, and the audience enjoys the stories). An experienced follow with an inexperienced leader can shift her focus to the music, and concentrate on adding style flourishes that don't confuse the leader.
The two forms of performance dancing are showcase and competition. Showcase is tightly choreographed, to a piece of music that the dancers know well, and the dancers and choreographer normally have the opportunity to plan nuances as subtle as raised eyebrows. In freestyle competitions the dancers don't know the music ahead of time, so the choreography is developed on the fly.
In performance dancing, the people being entertained are the audience (including judges). So the dancers need to include the audience in the dance. This is done through positioning and eye contact. There still needs to be a connection between the dancers (because that in itself is entertaining to the audience), but this is widened to include the audience.
Performance dancers generally have much more space available than social dancers, so floorcraft is less of a concern. The controlled space enables dancers to pull off moves that would be dangerous in a social environment.
Choice of moves
As a general guide, moves for performance dancing will be more dramatic and spectacular than those in social dancing. There will be more lifts, dips and drops. The couples will practice complex moves that look great when done right, but which could look awful if not done perfectly. There will also be more extension moves (so that both dancers are presenting to the audience). And depending on the situation, there may be more use of the floor space.
Line of dance
In social dance, the orientation of the dancers is irrelevant. But for performance, orientation is very important, because the dancers need to perform to the audience. So moves need to be orientated so that the audience can see the dancers' faces whenever possible.