Cats meow to communicate. They do it to communicate with you, your family, or other animals. Some breeds of cat tend to enjoy communicating more than other breeds. Siamese, Manx, and American Wirehair are just some of the cat breeds that meow more than the average feline.
If you spend enough time around your kitty you might notice different sounds of meows. Different meows mean different things. Some reasons for a meow include hunger, thirst, interest in something, disinterest in something, discomfort, contentment, and other things. What constitutes excessive meowing? That is up to you to decide after taking into consideration the breed, health, and stress of your animal.
A cat that is being transitioned to a new home might meow a lot at first. One that is being moved indoors from an outdoor life or from indoors to outdoors will probably make more noise than normal. This should fade as your pet adjusts to the new living arrangement. During breeding season he or she is probably searching for a mate. Consider getting your feline spayed or neutered if he or she isn't already. Make sure that your kitten is getting enough food to eat and has access to fresh water to drink. If there are people showing up or leaving regularly, the meow could be a greeting or a "goodbye." Older cats, sometimes, meow more because of health issues. Some of these issues are normal problems of aging and some require professional assistance. If you suspect this to be the case contact a qualified veterinarian.
Don't rule out that your pet cat might just be trying to get attention from someone. If this is the case continue to ignore your pets requests. If you give attention of any kind in return for meowing you are, only, going to get more meowing. This is assuming that your cat gets attention from someone at some times. If no one is paying any attention to him or her I urge you to consider finding another home for your feline. One thing to remember is to never use punishment to try to alter a pets behavior. Punishment and negative rewards will only get you more negative behavior.