When referring to video, analog is a way of storing audio and video information in a way that each variation to the signal effects the information. With digital, the signal is either on (representing a 1) or off (representing a 0). In analog, the signal could be anywhere on a range of thousands or millions of possibilities. Because light information is essentially analog when it enters the camcorder's CCD, analog equipment is more simple than digital equipment.
One of the disadvantages of analog recording is that the signals cannot be compressed. Analog video also gradually loses quality as it is played and stored, while digital can be stored for certain amounts of time with no change in the video information.
When transfering an analog video tape to another analog video tape, there is always some loss of quality. Digital video, on the other hand, does not lose quality as it is copied, as long as it is transfered digitally. This is because at any time there are many different possibilities for the analog signal, but the ditial signal is always on or off. There is always noise (random variations of the signal) involved when transfering video, but the digital signal allows for the noise to be removed.
While analog camcorders have been on the market for decades, digital camcorders have only been around since 1995.