If you're just starting out or had a lesson or two you're considered a beginner. A lot of volume in a board makes it float better, catch waves easier and provides a solid platform when learning the basics of riding a wave. A mistake many people make when buying their first surfboard is not getting enough volume. Longboards or fun boards (including minimals & foam boards) are the ideal blend of a forgiving shape combined with ample volume that is crucial in the early stages of surfing. Choosing the right length will depend on your weight (and age/fitness level) which is explained in more detail on the board pages.
As an intermediate surfer, you will be comfortable on your surf board and able to pick the waves you want with ease. Although consistently linking turns at this stage you should be looking to improve your overall flow and control as well as getting more critical with your manoeuvres. Larger boards limit progression at this stage and so it's time to drop some volume and fine tune the overall design. Ideal boards include Hybrids, fish as well as shortboards. Again, weight and fitness levels are crucial when picking the right board.
As an advanced surfer, you're experienced in a wide range of conditions. You are confident in your turns and manoeuvres, are able to hold your line in a barrel and show all around control in all conditions. You've probably been through a lot of boards over the years and generally know what you like to ride. These will usually be in the form of a shortboard - but sometimes a small hybrid or fish too. However, with new shapes on the market, especially in recent years - even the advanced surfer can find it hard to determine what board to ride. Volume again is the key to making the right decision and understanding your ideal "board volume" can help wonders when choosing that new stick.