The causes of rallies vary. Short-term rallies can result from news stories or events that create a short-term imbalance in supply and demand. Sizeable buying activity in a particular stock or sector by a large fund, or an introduction of a new product by a popular brand, can have a similar effect that results in a short-term rally. For example, almost every time Apple Inc. has launched a new iPhone, its stock has enjoyed a rally over the following months.
There are two main forms: stage rallies and road rallies. Since the 1960s, stage rallies have been the professional branch of the sport. They are based on straightforward speed over stretches of road closed to other traffic. These may vary from asphalt mountain passes to rough forest tracks, from ice and snow to desert sand, each chosen to provide an enjoyable challenge for the crew and a test of the car's performance and reliability.
Most of the works drivers of the 1950s were amateurs, paid little or nothing, reimbursed their expenses and given bonuses for winning (although there were certainly exceptions, such as the Grand Prix drivers who were brought in for some events). Then in 1960 came arguably the first rallying superstar (and one of the first to be paid to rally full-time), Sweden's Erik Carlsson, driving for Saab.