Many people walk into a tackle store looking for a new rod then get utterly confused when store staff start talking about rod tapers or actions. Most fishermen refer to this as how flexible or stiff a rod is.
Rod action refers to how a rod bends and flexes under load. Slow or soft rods flex and bend the entire length of the rod whereas fast tapered rods mainly flex at the tip and are stiffer from butt to mid section. Rod actions are made to suit the type of fishing an angler is doing.
One must take into account how a rod will be used. Will the rod will be used more for casting than trolling, or maybe it will be used primarily for bait fishing. Each style really does need a different action to get the best from your rod. This in turn can give you some advantages such as casting distance and fish playing ability.
For bait fishing a moderate to slower tapered rod should be used as this allows fish to pick up baits and take some line without pulling hooks-the rod will bend easily with the take.
Trolling rods for estuaries and freshwater should be of a moderate taper so there is some give when the fish hits the lure whilst it is moving. Don't use a rod that is too slow as often the fish will not hook up properly-the rod tip will bounce on the take and you will find more missed hits than hook ups. I believe this is one of the reasons why many anglers started trolling with single hooks thinking that the trebles were failing but I believe the rod was more likely to blame. For some reason some anglers like a soft glass rod for trolling in freshwater as they like to see the rod tip bouncing or pulsing indicating to them the lure is working. Believe me, a lure still works just as well, or better, on a moderate taper but you will get more positive hook ups.
Spinning rods will also vary, for lighter lures like bladed Celta types a rod with a moderate to slow taper will cast further with light line than a rod that is extra fast. But this will change when fishing with bibbed style lures like Rapalas or even lures like Tassie Devils. A moderate to fast tapered rod will serve these lures better because of the extra weight you are casting.
When it comes to soft plastics nearly all factory built rods are fast to extra fast in taper this is because the lure will work with more control with the small hand movements used whilst retrieving a soft plastic. A rod that is too soft will have the soft plastic bouncing all over the place with little control by the angler. I've even heard recently of people converting fly rod blanks to become soft plastic rods and I couldn't think of fishing with anything worse for this type of angling. Yeah sure you may catch the odd fish but you'll catch a hell of a lot more if you use a rod that's designed by taper to do what's its intend to do. Anglers should remember that whilst we may all have our own opinions fishing rods these days are computer designed for optimum performance and we should not forget that. Tackle store staff should ask you when you are purchasing a rod what type of fishing is intended so they can then direct you to rods that will satisfy your needs best.
So basically rod taper is important for several reasons fast actions rods particularly those made from graphite will control lures better and with more feel, whilst softer rods are great for fishing for bigger fish when your using light line as the softer rod will absorb the shock of a fish lunging away. So when purchasing a new be sure to consider what taper and action will best suit your needs.